FLC Technology FLC 8S

  1. Brooko
    FLC8S – Versatility to the Extreme
    Written by Brooko
    Published Jun 15, 2016
    Pros - Versatility in tuning, comfort, clarity and resolution, bass quality and speed
    Cons - Microphonic tangly cable, tuning parts very small + easy to break/lose, tweezers are useless, mid-range limited tuning with existing filters/bores
    For larger views of the photos (1200 x 800) - please click on the individual images


    The FLC8S was one of those IEMs which burst onto the scene with practically no warning, and before I knew it, had become very popular with a very loyal and vocal fan base. I wanted to try them for the purposes of a review (to see if the tuning did indeed live up to the hype) – but I've had a policy of not soliciting review samples for a while now (preferring vendors to approach me). Some may think this strange, but in my own way I find it easier to be objective if I have no obligation to the manufacturer. Lets just call it one of my quirks.
    So my thanks for the opportunity to review the FLC8S go out first and foremost to Forrest Wei for approaching me, and sending the sample, and second to Djscope and nmatheis for both contacting Forrest and recommending me. I really appreciated the chance to hear them.
    Finding a lot of information about the Company is pretty difficult – Google didn't turn up a lot of hits – just a lot of very positive reviews about their products (always a good sign). So for the most part the following is taken from a number of different websites and also some info about Forrest borrowed from Nik's very good review. FLC really is based around Forrest Wei's mastery of tuning and design – and his list of credentials is very impressive. Over the years, he has worked at companies including Ultimate Ears, Harmon and Jabra – and been heavily involved in designing and tuning both universal and custom in-ear monitors. Anyone who's heard the Oriveti Primacy will possibly also recognise some of his tuning in that earphone as well (distinctive 1-2 kHz bump). One of Forrest's goals has been to sell an affordable IEM with enough tuning options to give the user the ultimate choice in the final signature. This goal was realised with the release of the FLC8S I'm reviewing today.
    The FLC8S that I’m reviewing today was provided to me gratis as a review sample. I have made it clear to FLC that I still regard any product they send me as their sole property and available for return any time at their request. But I thank them for the ability to continue use of the FLC8S for follow up comparisons. I do not make any financial gain from this review – it is has been written simply as my way of providing feedback both to the Head-Fi community and also FLC themselves. I do acknowledge that t is extremely unlikely that FLC will ask for the IEM to be returned, so for all intents and purposes it is provided freely.
    I have now had the FLC8S since February. The retail price at time of review is USD 360.00 (Lend me UR Ears), or USD 340.00 (Shenzhen Audio)
    I'm a 49 year old music lover. I don't say audiophile – I just love my music. Over the last couple of years, I have slowly changed from cheaper listening set-ups to my current set-up. I vary my listening from portables (including the FiiO X5ii, X3ii, X7, LP5 Pro and L3, and iPhone 5S) to my desk-top's set-up (PC > USB > iFi iDSD). I also use a portable set-up at work – usually either X3ii/X7/L3 > HP, or PC > E17K > HP. My main full sized headphones at the time of writing are the Beyerdynamic T1, Sennheiser HD600 & HD630VB, and AKG K553. Most of my portable listening is done with IEMs, and lately it has mainly been with the Jays q-Jays, Alclair Curve2 and Adel U6. A full list of the gear I have owned (past and present is listed in my Head-Fi profile).
    I have very eclectic music tastes listening to a variety from classical/opera and jazz, to grunge and general rock. I listen to a lot of blues, jazz, folk music, classic rock, indie and alternative rock. I am particularly fond of female vocals. I generally tend toward cans that are relatively neutral/balanced, but I do have a fondness for clarity, and suspect I might have slight ‘treble-head’ preferences. I am not treble sensitive (at all), and in the past have really enjoyed headphones like the K701, SR325i, and of course the T1 and DT880. I have a specific sensitivity to the 2-3 kHz frequency area (most humans do) but my sensitivity is particularly strong, and I tend to like a relatively flat mid-range with slight elevation in the upper-mids around this area.
    I have extensively tested myself (ABX) and I find aac256 or higher to be completely transparent. I do use exclusively red-book 16/44.1 if space is not an issue. All of my music is legally purchased (mostly CD – the rest FLAC purchased on-line). I tend to be sceptical about audiophile ‘claims’, don’t generally believe in burn-in, have never heard a difference with different cables, and would rather test myself blind on perceived differences. I am not a ‘golden eared listener’. I suffer from mild tinnitus, and at 49, my hearing is less than perfect (it only extends to around 14 kHz nowadays).
    For the purposes of this review - I mainly used the FLC8S straight from the headphone-out socket of my FiiO X3ii + E17K and/or X3ii + IMS Hybrid Valve Amp , and also used (at different times) my iPhone 5S, and a variety of the other DAPs I have around me. Although I tested them with an amplifier, I do not think they benefit from additional amplification (I use mine mainly for consistency when reviewing and also to extend battery life on the X3ii). In the time I have spent with the FLC8S, I have noticed no changes in the overall sonic presentation, but am aware that I am also becoming more used to the signature of the FLC8S as I use them more often (brain burn-in).
    This is a purely subjective review - my gear, my ears, and my experience. Please take it all with a grain of salt - especially if it does not match your own experience.


    The FLC8S arrived in one of the most unique boxes I've come across in over 100 audio reviews. At first glance it looks like a beige rectangular cube – sort of like an outer shipping box – measuring approx 160 x 130 x 90 mm. It has the FLC logo on the top and sides, and the simple description “Hybrid Headset”.
    flc8s01.jpg flc8s02.jpg flc8s03.jpg
    The quite plain looking box
    Top lid flipped open to reveal the FLC8S
    Pressing down on the foam reveals a hidden compartment

    At the bottom left of the front face is a simple instruction to “open here”. Lifting this cover reveals the FLC8S safely nestles in a form-fitting blue foam top section. On the foam is neatly labeled “press here” - and this reveals a second small compartment holding the tweezers and cable. OK – I was a bit lost, what about the accessories and filters? Then I noticed the bottom left again – once again telling me to “open here”. This revealed there was an upper tray and lower tray – with the lower tray opening like an older style jewellery box. The bottom tray housed the instruction manual, case (which holds the tips and other accessories), and the clever filter holder.
    flc8s04.jpg flc8s05.jpg flc8s06.jpg
    The original foam layer flipped to reveal cable
    Box opened right out to reveal lower cavity
    Bottom cavity holding case and filter holder

    The entire package is incredibly comprehensive and includes:
    1. The FLC8S
    2. The metal alloy screw top carry case
    3. The metal alloy filter holder (also screw top)
    4. 4 sets of clear silicone tips (L, M S, VS)
    5. 4 sets of black silicone tips (L, M S, VS)
    6. 1 4-core replaceable cable (twisted)
    7. 1 cleaning tool
    8. 1 airline adaptor
    9. 1 3.5-6.3 mm adaptor
    10. 3 pairs ULF tuning plugs (with a couple of spares)
    11. 3 pairs LF tuning plugs (with a couple of spares)\
    12. 4 pairs MF/HF tuning bores
    flc8s07.jpg flc8s08.jpg flc8s09.jpg
    All the accessories
    The very sturdy FLC8S case
    Case top (you can just make out the subtle FLC etching

    The carry case is incredibly solid, and quite large – 80mm diameter and just under 40mm in height – so it is more transportable than portable (not really pants pocket friendly), but it is perfect for protection and I've used it a lot for transport between home and work. It is nicely lined with soft felt for protection.
    The filter case is likewise solidly built and comprises a capsule with screw on top, and inside is a mould which has enough room to house 3 pairs of tuning bores, and 2 pairs of each of the ULF and LF tuning plugs. For most people this is ideal, as they'll have the others fitted on the FLC8S – but when we come to the tuning section I'll explain why I would have personally liked room for another couple.
    flc8s34.jpg flc8s10.jpg flc8s13.jpg
    Tip selection
    Very good FCL manual (more on that later)
    The filter holder / fob.

    Overall – the packaging is unique, very comprehensive, and looks like it covers everything you're likely to need.
    (From FLC)
    Hybrid dual BA + 8.6mm Dynamic Driver
    Frequency Range
    20 Hz – 20 kHz
    11 ohm
    117 dB @ 1kHz 1mW
    1.2m 4 core single twisted copper (replaceable)
    3.5mm gold plated, straight jack
    Approx 14g with tips in place
    IEM Shell
    Hi-gloss strengthened plastic

    The FLC8S is made in either high gloss blue or high gloss red, and at first glance you'd think it was made of polished coloured aluminium. But once you have it in your hand, the extremely light weight and feel confirms it is actually a moulded two piece plastic shell. Each earpiece is very ergonomic – designed to fit the contours of the ears, and it is clear that Forrest has taken great pains to ensure the shell is well rounded and without sharp edges.
    flc8s19.jpg flc8s20.jpg flc8s21.jpg
    Shell showing the 3 filter placement choices
    Side view back and front - showing nozzle extension
    Internal side - note left/right markings

    The shell (without cable) measures approx 18 mm long, 18mm from top to bottom, and the main body is only around 10mm deep – with the nozzle extending a further 8-9mm. The body is L shaped, and the nozzle is perpendicular to the main body (rather than angled). There is one port on the external face which houses the LF tuning plug, and one port on the internal face with houses the ULF tuning plug. The nozzle has no lip, but is threaded, and the lip is provided by the addition of the tuning filter bores (which simply screw in place).
    flc8s22.jpg flc8s23.jpg flc8s24.jpg
    Nozzles upright - note the very smooth rounded surfaces
    Main bore/filter fitting - screw in
    ULF filter placement

    Each IEM internal face has a L or R indicator stamped into the body mould adjacent to the cable connection socket. This socket is two pin, and takes 0.75mm pins – I.E. the same configuration as the UE TF10. The sockets are raised, with the cable plugs fitting snugly over the top for added strength. The cables also have L or R printed on the outer plug housing.
    flc8s25.jpg flc8s26.jpg flc8s27.jpg
    LF filter placement
    MF/LF filters create natural lip for tips
    Cable guides and TF10 type connector

    Each cable has 75mm of formable memory wire for form fitting over your ears, and I find this quite handy for getting them to sit correctly when worn. The cable is 4 core single twisted copper strands in continuous twist from the plugs to the jack (the twisted pair becomes a twisted quad below the Y-split) which allows a simple replacement of the jack to convert to balanced.. Unfortunately the cable, while quite flexible, is also both microphonic, and also retains a lot of memory making it quite unruly. It tends to retain any kinks and can be quite difficult to fully straighten. One of the photos below shows the FLC8S next to the MEE P1.  Both were nicely coiled when I gently placed them in the light box. Its sad such a great design has such a poor cable.
    flc8s28.jpg flc8s29.jpg flc8s31.jpg
    Another view of the cable connection
    The unruly cable next to the MEE P1 (beautifully coiled)
    The 4 strand cable - easy to balance

    The Y-split is a simple piece of heat-shrink, which is quite effective, and has another piece of clear plastic tube above it for a cinch – but unfortunately this does not work well with the cable jack (it is too tight – and therefore too hard to effectively move). The jack is right angled, gold plated, and has both good strain relief, and also is smart-phone case friendly.
    flc8s32.jpg flc8s30.jpg flc8s18.jpg
    Y-split and cinch
    Jack next to filters (so you can see how small they are)

    All in all, the build quality is pretty good and seems nicely robust. I'm not overly fond of the cable, and if this was to become my daily use IEM, the first thing I would do is to replace it with something having less microphonic and unwanted memory tendencies. For the price, it is one of the weaker points in an otherwise very good build.
    The ergonomic shape of the FLC8S combined with the light weight, and well rounded surfaces make this IEM one of the most comfortable I've ever worn. If you take the time to properly mould the memory wire, it sits perfectly on my ears, and is definitely flat with my outer ear (which allows me to lay easily on my side with the IEM's intact). About the only slight issue I've found with the FLC8S is that it has a tendency over time to slowly push the preferred foam tips I use out of my ears. They never push all the way out, and don't usually break the seal – but I do wonder if the nozzles were slightly angled maybe the issue would disappear. Something for Forrest to consider with subsequent releases perhaps.
    flc8s35.jpg flc8s36.jpg flc8s37.jpg
    Spinfits and Sony isolation tips both worked
    as did Spiral Dots and Ostry tuning tips
    My preferred foams which also worked with no filter/bore

    If I was using any of the tuning bores, they all come with a slightly serrated metal edge which allows for easy grip when fitting or removing – and this acts as a lip for the nozzle. This means that practically any tip will fit, and this includes smaller bore tips like Spinfits or Sony Isolation tips. And this also applies to Ostry tuning tips and even wider bore Spiral Dots. My preferred foams also fit well, and the only downside was that if you are using a foam tip, and change filters often, the serrated edge can tend to pull the internal bore tube out of the foam tips. Because I had to make so many changes when I was measuring all the filters – I actually destroyed two pairs of generic foam tips.
    The one thing that some may not know is that you can also use the FLC8S without any internal bore filter fitted. There is enough of the nozzle to accommodate a tip but using this method means there is no lip. Fortunately for me foam tips fit well, and this has become my preferred default configuration.
    Isolation with the FLC8S will depend on the seal you achieve, insertion depth, and also the choice of filters. Being a ported design with a shallow fit, I'd describe the isolation as adequate or average – without being excellent (few hybrids are). With music playing, you're isolated pretty well. They would be good for most public transport but I personally wouldn't be using the FLC8S for long haul flights.
    So the new FLC8S looks good, has a good build, and is extremely comfortable to wear. Let’s have a quick look at my initial impressions, then take a look at the filters in more depth, and then move onto sonic impressions.
    So the FLC8S had just arrived, I was keen on seeing how the filters worked, so I grabbed the included tweezers and attempted to remove the first ULF filter. Crack – plastic filter snapped at the head and was basically ruined. Thankfully there was a spare red one. So first lesson learned – the included tweezers are unwieldy, and basically there as a decoration (for me anyway, they are simply too big and pretty much useless). Much easier to simply use your finger nails.
    So I carefully put a white cloth down, and proceeded to remove the red ULF and inset a clear. Slightly missed the hole (they are tricky) – said filter ricochetted off the housing, and disappeared into our carpet. After 10 minutes searching I gave up (thankfully again Forrest had included spares), so from that point on I have been super careful both removing and fitting the filters plugs, and haven't lost or broken another one yet. But word to the wise – these are really tiny, not easy to grip in bigger fingers, and quite frustrating at times to fit. Forrest – if you had a system where you could have a fixed dial with 3 or 4 settings, and the dial stayed intact – that would be a far nicer system! But I still have to give it to Forrest and his team – the “tweakability” of the filter combinations is quite incredible – and that is what makes this IEM so unique. So lets look a little more in depth at the filter system
    The FLC8S comes with 3 different options for controlling the sound – an ultra low frequency port (ULF), a low frequency port (LF), and the tuning bores which control mid-range and high frequencies (MF/HF). Forrest advertises 36 different combinations and you have 3 ULF plugs, 3 LF plugs, and 4 MF/HF bores – so using simple math that gives 3 x 3 x 4 = 36 combinations right. Well actually not quite. The LF can be used without a plug, and it has another subtle change to the mid-bass. Also the nozzle can be used without a bore at all (I'll show you in a minute why I prefer it that way) – and that has quite a change on the frequency response. You could also remove the ULF filter – but I'm not counting that as an options as it cripples the sound. So the reality of tuning now is 3 (LF) x 4 (LF) x 5 (MF/HF) = a massive 60 different tuning combos.
    flc8s14.jpg flc8s15.jpg flc8s17.jpg
    MF/HF filters
    ULF filters
    LF filters

    The only problem is that trying to make sense of all those options can simply be too daunting. But thankfully Forrest includes some recommended options and combos on the instruction manual – see the images.
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    Explanation of filters from the manual
    Forrest's recommendations (see graphs at bottom of review)
    Channel matching is excellent

    Looking at the filters themselves – this is how they stack up:
    Red plug
    Most sub-bass
    Grey plug
    Medium sub-bass
    Clear plug
    Least Sub-bass
    No filter
    Most mid-bass
    Black plug
    Medium/high mid-bass
    Grey plug
    Medium/low mid-bass
    Clear plug
    Least (flattest) mid-bass
    Gold bore
    Most MF and medium HF
    Green bore
    Most HF and medium MF
    Black bore
    Medium MF and medium HF
    Blue bore
    Least HF
    No Bore
    Moves MF and relatively high HF

    But the easiest way I can show you what I’ve found is simply to show the comparative changes by graphing them. The graphs below are generated using the Vibro Veritas coupler and ARTA software. I must stress that they aren’t calibrated to IEC measurement standards, but the raw data I’m getting has been very consistent, and is actually not too far away from the raw data measured by other systems except for above 4-5 kHz where it shows significantly lower than measurements performed on a properly calibrated rig. So when reading the graphs, don’t take them as gospel – or at least remember that the area above 4-5 kHz will likely be significantly higher. It is my aim to get this system calibrated at some stage in the future.
    The graphs are provided merely as a point of discussion, and should be used for comparative results only – they do not reflect the true calibrated frequency response(particularly above 4-5 kHz). For each setting I've used the most neutral filters for the other settings (grey LF, grey ULF, and black MF/HF) as controls and then shown the range of filter options for the single filter being tested.
    ULF filter
    Three options – clear, grey and red. They are all a straight plastic, very small and fiddly to fit, and you do need to handle them relatively carefully (easy to lose and can break). They control the sub-bass pretty well, and their overall curves are very dependent of the LF filter used in tandem. The red filter has the most rise, and this does add some slam. The grey extends pretty well before a slow roll-off around 40 Hz. The clear has the least, but can also be the most natural depending on which LF (mid-bass) filter you use.
    LF filter
    Although there are 3 actual filters, in reality there is 4 viable options – clear, grey, black and none. The actual filters themselves are small, rubbery, and the hardest to fit. Often I found the black and grey filters quite close to each other (the graph shows it too), but you an get more variation when combined with different ULF filters. Once again the clear has the least mid-bass, and TBH the only time I really liked this one was when combined with the red ULF (creates a very flat bass signature). Using no filter here gives the most mid-bass, and as you'll see later in the review, provides some surprising results when configured to my liking.
    MF/HF filter/bores
    Easiest to fit, and 4 physical options – with each filter being just under 10mm long, and screw directly into the nozzle, creating a natural lip to retain the tips. Personally for me (while they were pretty good), none were perfect. My issue (and this is purely my preference) is that each filter had a bump to a varying degree between 1-2 kHz, then a drop-off between 2-3 kHz. You'll notice many earphones are often flat between 800 Hz and about 1.5 kHz before rising as they head toward 2 kHz. The reason for that is that the mid-range is where we are most sensitive anyway, and while boosting between 1-2 kHz can create heightened clarity around the vocal area, some can find this a little fatiguing, and it can also narrow the perception of sound-stage – bringing the vocalist too close. The other issue with bumping the 1-2 kHz area, is that if it is not followed with a subsequent rise (or at least flat) section in the 2-3 kHz area, you can lose some presence or sweetness - especially with female vocalists. The one thing I do like about these filters though is the way they provide options in the lower treble. Your choice will often be dictated by how sensitive you are to brightness, with the green being the brightest and blue the smoothest. I personally find the filter with the best overall cohesion between upper and lower mids is the green filter. It has the least bump at 1-2 kHz and it is tempered by a secondary small rise in the 2-3 kHz range which helps with presence, but unfortunately it comes with a cost of heightened treble.
    Fortunately there is another option which involves removing the MF/HF bore altogether. This removes the 1-2 kHz bump, and leaves you with a rise at 2-3 kHz, but unfortunately also a big rise at around 7-8 kHz (which is quite a peak).
    Real Versatility
    And here is where I can show you how truly versatile the FLC8S really is. My ideal signature is a relatively flat bass with a slight mid-bass hump, and either flat extension through to sub-bass or slight roll-off. For mid-range I'm OK with a slight recession between the mid-bass hump and (hopefully) a nice gentle rise in the presence area at 2-3 kHz. After that – the lower treble area often doesn't matter as much to me, as long as there is enough presence to hear good decay on cymbals, and hopefully not trigger my sibilance areas. It's not surprising that many other earphones also mimic this type of response. Well choosing the clear ULF with no LF filter, and then no MF/HF filter gives an almost perfect curve. The clear ULF (least impact) combined with no LF (most mid-bass) gives a really nice flat curve with a gentle (and very natural sounding) mid-bass. And this combo with the mid-range bump moved into the presence area gives almost perfect balance. And in reality starts almost sounding HD600 like. It's not perfect – but for me it is something I can listen to for hours on end – and that is the magic of Forrest's filter system. My only wish is that there were a few more options with the bump in the 2-3 kHz area. Anyway – I've graphed my preference against the red/black/gold that many have talked about as being one of their favourite signatures. And remember I said I would have liked more room in the filter holder? This is simply because I have 2 HF/LF filter bores and 2 LF filters which I'm not using, and are effectively “spares”.
    The great things is that there is no right or wrong – you set the FLC8S up the way you like it.
    With 11 ohms impedance and 117 dB sensitivity, you can run the FLC8S from any source – power is simply not an issue. The one thing you will need to take into account though is the 11 ohm impedance – which suggests an ideal damping ratio of around 1ohm or less on your source. With typical pop/rock songs on the iP5S I’m usually at a volume level of around 25-35%, on the X3ii around 30-40/120. I did try amping with the E17K and IMS Hybrid Valve amp, and while I noticed no obvious signs of improvement from a driving point of view, both amps were pretty good matches for tonality. The Hybrid Valve amp brought a slightly softer tonality to the lower treble peak ( a really nice combo actually), and with the E17K I could apply -2 or -4 treble, and just soften the same peak. The result was brilliant. So overall I'd recommend amplification if you simply want to adjust the tonality a little, or if you have issues with high impedance on your normal source's output. You won't need it for the power.
    It doesn't need it – and that is what the filters are for. But as I outlined above, it can be useful for smoothing peaks if you need to.
    The following is what I hear from the FLC8S. YMMV – and probably will – as my tastes are likely different to yours (read the preamble I gave earlier for a baseline). Most of the testing at this point (unless otherwise stated) was done with my FiiO X3ii + IMS Hybrid Valve amp as source.
    Tracks used were across a variety of genres – and can be viewed in this list http://www.head-fi.org/a/brookos-test-tracks.
    The filter set-up I used was clear, none, none as outlined above in the filter section. I actually thought a lot about skipping this section altogether – but thought it was still important to write my thoughts on what is for me the best filter combo.
    Thoughts on General Signature
    The sound signature with this filter combination is well balanced with a slight tendency toward brightness, incredibly clean and clear, and tilted slightly toward more presence for female vocals (male vocals are still very good but have slightly less presence). Mid bass sounds beautifully natural with enough thump to be pleasing, but without anything dominating. Sub-bass is there, but again balanced and does not dominate.
    Overall Detail / Clarity
    Tracks used: Gaucho, Sultans of Swing
    1. Very, very clean presence and presentation with perfect balance and real cohesion between bass, mid-range (vocals), and upper end detail (hi-hats/cymbals).
    2. Extremely good detail retrieval with every nuance shown but not etched (it still sounds very natural). Cymbals are incredible – especially the decay.
    3. Guitar has wonderful edge – crisp and clean
    4. Vocals in both tracks are nicely presented in contrast to the rest of the track, and blend naturally.
    Sound-stage, Imaging, and Sibilance Test
    Tracks used: Tundra, Dante’s Prayer, Let it Rain
    1. Very precise directional cues, just outside the periphery of my head space – so very good feeling of width and reasonable feeling of depth.
    2. Imaging is incredibly clean and clear and excellent separation of instruments without being clinical.
    3. Dante's Prayer was practically perfect with stunning contrast between the cello, piano, and Loreena's excellent vocals.
    4. Good immersion (applause section of Dante's Prayer) with impression that crowd is around you (you are sitting right in it). Probably a little more width than depth, but good none the less.
    5. Sibilance is present in “Let It Rain” - I know it exists in the recording. However it isn't overly emphasised, and for me is very tolerable.
    Bass Quality and Quantity
    Tracks used: Bleeding Muddy Water, Royals
    1. Very good mid-bass impact and great portrayal of the overall dark mood. Mark's vocals have wonderful presentation of timbre, and texture (“Muddy Waters”) and whist they may not be as deep as I have heard them before, I am really enjoying this particular presentation.
    2. Good speed and bass resolution – not too boomy, but there is slight decay present.
    3. No signs of bass bleed into the mid-range
    4. Surprisingly good sub-bass (even with this filter combo) for rumble (“Royals”) but not over-done (perfect balance actually).
    5. Ella's vocals are incredibly presented – with good separation from mid-bass impact.
    Female Vocals
    Tracks used : Aventine, Strong, For You, Human, The Bad In Each Other, Howl, Safer, Light as a Feather, Don’t Wake me Up, Ship To Wreck.
    1. Wonderful transition from lower-mids to upper-mids – this is one of the strengths of the FLC8S with this filter combo
    2. Very euphonic presentation with good air and a wonderful touch of sweetness to female vocals
    3. Brilliant contrast between vocals and lower pitch of instruments like cello
    4. No signs of stridency with Aventine and Strong
    5. Really good mid-bass impact with music with highly dynamic content (Feist, FaTM) – contrast between bass and vocals is excellent.
    6. Superb with slower female vocals and especially with artists like Gabriella Cilmi, Norah Jones and Sarah Jarosz.
    7. I could listen to this filter combo for hours with any of my female artists. It's not just good, it's practically perfect.
    Male Vocals
    Track used: Away From the Sun, Art for Art’s Sake, Broken Wings, Hotel California, Immortality (Seether), Keith Don’t Go, Elderly Woman Behind the Counter in a Small Town.
    1. Presentation of male vocals will depend on how you normally like them, but this tuning is really extremely good and I'm appreciating how well this particular tuning does both male and female vocals without thinning either one.
    2. Bass presence is impactful from the mid-bass, and this provides good contrast with lead guitar.
    3. Excellent portrayal of classic rock artists like 10CC and Jethro Tull. Mix of detail and tonality is very good.
    4. Brilliant with acoustic tracks – especially Eagle's Hotel California. Spatial cues are very good with this live track too
    5. Showed a little thinness with Seether's cover of Immortality, but it doesn't take long to get used to the tonality and is still very enjoyable.
    6. Love the balance with Pearl Jam – and the texture and tonality with Eddie's vocals is very good. Cymbal decay was magic in this track (there is a lot of it). Another band I could listen to for hours. So clean and clear, and I think this is what really makes all vocal tracks stand out.
    Other Genre Specific Notes
    1. Not going to go through all of these – as this is just such a great all-rounder
    2. Particularly strong with Jazz and Blues
    3. Loved classical – airy, detailed, sombre when it needed to be, light and deft for stringed ensembles.
    4. Would possibly add a bit more sub-bass for some electronic, hip-hop, trance or dub (just a matter of dropping the red filter in)
    5. Indie could get a bit peaky – depending on the recording, but easy fix if used with the E17K, or simply dropping the 7-8 kHz peak down with EQ.
    This section is practically impossible to write as you can change the outcome depending on the filters. So instead I thought I'd stick with my favoured filter combo, and show you why I like it (by comparing it with some other reasonably well-known IEMs).
    All of these comparisons are very subjective – and influenced by my own preference, physiology and bias. Comparison was once again with the X3ii + IMS HVA. All IEMs were volume matched with a 1 kHz tone and using a proper SPL meter (I used a splitter and variable resistor so I could swap back and forth quickly). The reason I chose each of these for comparison was very simple – all of them have roughly similar to this particular filter combo.
    FLC8S (~$340) vs DUNU Titan 5 ($140)
    flc8s39.jpg vstitan5.png
    FLC8S next to DUNU Titan 5
    Graphed comparative frequency response

    While the Titan 5 is less than half the price, it was one I though of immediately because tonally these sound extremely familiar. On build quality, the T5 has the advantage with the full metal shell, and it has a much better cable than the FLC8S. Fit on both is good and I'd be hard pressed to find a winner on the comfort stakes. Sonically the two IEMs are incredibly similar with the T5 having a little more sub-bass slam, while the FLC8S might have a little more mid-bass impact. They both have an incredibly similar mid-range with the same excellence overall in vocal presentation. The T5 is a little less spacious, a little more vivid, and a little brighter in its overall presentation. If I was shopping for one sound only, I'd probably pick the T5 – but the beauty of the FLC8S is that this is just one of the signatures it can mimic. If you are a tweaker – the extra outlay is worth it.
    FLC8S (~$340) vs Fidue A83 ($270)
    flc8s40.jpg vsa83.png
    FLC8S next to Fidue A83 ​
    Graphed comparative frequency response​

    This time we're triple hybrid vs triple hybrid, and I think a few might be a little surprised with the similarity here between the FLC8S and Fidue's former flagship. Both have similar build quality and comfort. The FLC8S has the better cable connection system (Fidue had past issues with the MMCX connectors), but the Fidue has the better default cable (although I am now using one of Trinity Audio's). Sonically there are similar traits in the bass, transition to mid-range, and even the lower treble. The difference primarily is in overall speed (the FLC8S just seems to have quicker transitions), in mid-range weight (the A83 is slightly thicker but also more vivid), and in clarity and cleanliness of tone (the FLC8S is simply cleaner and clearer). Although the Fidue is quite a bit cheaper, this time it isn't a fair comparison. The added versatility of the FLC8S simply trumps the A83 – although both remain excellent choices.
    FLC8S (~$340) vs DUNU DN-2000J ($300)
    flc8s41.jpg vsdn2000j.png
    FLC8S next to DUNU DN-2000J​
    Graphed comparative frequency response​

    Again this is triple hybrid vs triple hybrid, and for this one I couldn't use the splitter because plugging both at the same time affected the bass response (both being very low impedance), so I had to plug and unplug. Build quality overall once again goes to the DUNU – the all metal build and quality of the cable is simply better than the plastic shell and unruly FLC8S cable (despite the 2000J cable not being removable). Comfort is with the FLC8S though with the better ergonomic fit. Sonically both are similar sounding from bass through to mid-range, with the main difference being in the upper mid-range transition through to lower treble. The 2000J has more heat in this area and this is something I haven't really noticed a lot in the past, but which is very apparent now that I'm used to the FLC8S. Switching between the two, I would call the 2000J slightly peakier and also the FLC8S a little cleaner sounding (and that is quite some achievement). Hard to pick a winner based on this filter combo, but again taking into account the versatility of the filter tuning it is really hard to go past the FLC8S – even compared to an IEM I absolutely love.


    My time with the FLC8S has been a revelation – frustrating at times, but with plenty of “aha”moments along the way, and while I was somewhat less impressed at first, I've grown to slowly appreciate it more and more as time has gone by.
    The overall build quality is very good despite its plastic shell, and the ergonomics really are top notch – very comfortable overall. The one issue (which many have commented on) is the cable. It is simply very unruly, retaining too much memory, and having slightly too much microphonic noise to be acceptable on an IEM in this price range. If there is one glaring thing Forrest should change first it would be the cable. Something well built and flexible like the Trinity cables or MEE P1 would be ideal IMO.
    The real value of the FLC8S though is its filter system, and while they can be cumbersome to change, and confusing with so many options available, once you get used to them you can definitely tweak the sound a lot to match your preferences. My only gripe with the filters (aside from the fiddly nature) is that the tuning bores all have the same or similar 1-2 kHz bump which I personally find OK short-term but fatiguing long-term. In fact if I didn't have the ability to change this one particular trait, I would not be as positive towards this IEM as I am now.
    The FLC8S won't be for everyone – you have to be prepared to experiment (a lot). It definitely helps to have a knowledge of the type of signature you like, and for me – my measurement system really helped me nail down the ideal combo.
    So would I recommend this IEM – unreservedly so. While it is not perfect, the versatility you get for the asking price is well worth it. An easy 4 stars for me (with an extra 0.5 added for the innovation) – and all it would take would be inclusion of filters to move that mid-range a bit, as well as a decent cable, and this would be an easy 5 star review.
    Well done Forrest – innovative, unique and truly well thought out. Thank you for giving me the chance to listen to and evaluate your creation.
    The following graphs are my measurements of Forrest's default recommendations.  They show some of the versatility of the FLC8S:
    vocal.png poprap.png piano.png
    Clear, clear, gold = vocal
    Grey, black, gold = pop/rap
    Clear, clear, green = piano or strings

    light.png default.png classical.png
    Clear, clear, black = light music
    Grey, grey, black = default
    Red, grey, green = classical

      Katie88, Asphalt, MidFiMoney and 21 others like this.
    1. View previous replies...
    2. TheoBungle
      Hello Brooko, thanks for the detailed review! I currently have the DN-1000s and GR07 BE and I would like to upgrade. I really like the DUNU’s bass and clarity and the GR07’s soundstage and balance. Ideally, I would like a (slightly v-shaped) IEM with articulate bass, not so prominent mids, brightish treble, wide soundstage and more “character” than the DN1000s. Would you recommend the FLC8s over the Pinnacle P1 or the 2000J? Cheers!
      TheoBungle, Sep 15, 2016
    3. Brooko
      Hi Theo - you just pretty much described the P1. The mids on the FLC8S might be slightly too prominent for you - they are quite forward.
      Brooko, Sep 18, 2016
    4. TheoBungle
      TheoBungle, Sep 19, 2016
  2. SerenaxD
    Under-appreciated end game IEMs at a reasonable price
    Written by SerenaxD
    Published Dec 9, 2015
    Pros - Sound, Versatility
    Cons - Memory wire makes fitting harder
    Product link: http://www.lendmeurears.com/flc-8s/ (apparently currently out of stock)
    So... This is my first time writing a review after lurking in the depths of Head-fi for three years, so bear with me [​IMG]
    A bit about myself - I'm a female student from HK studying in the US. I mainly listen to classical, instrumental and pop, and in general I tend to enjoy headphones that are balanced with a touch of warmth. I also value a wide soundstage, accurate positioning, and to a slightly lesser degree clarity and micro-detail retrieval. I should also mention that I'm not very tolerant towards sibilance and shrill treble in general. As a student I can't really get expensive gear all the time, so the FLC8S are my second pair of top-tier IEMs. I got these during the "Double 11" Chinese holiday discount, when these were priced at USD $250. These have over 50 hours of burn-in, most likely 100 hours, on them. 
    The FLC8S, from FLC Technology, is a dual BA/single dynamic hybrid released this year. Its biggest selling point was the 36 different sound signatures that you could switch between by way of nozzles and filters. It's been reviewed by ljokerl in his huge IEM thread, but they haven't received much attention around here, even though I feel like they're one of the best universal IEMs I've ever listened to. As such, I've decided to write a review on these, so that more head-fiers can get to know and appreciate this pair of amazing IEMs. 
    Setup used: 
    Portable: LG G4 --> Dragonfly 1.0
    Desktop: MacBook Air --> Objective2 Combo
    Appearance, Build Quality and Fit 
    I don't have the packaging with me right now, so sadly I don't have pictures of the box. It did come very nicely packaged with a three-layer intricate box. There was a little plastic bag of tips in 4 sizes (XS, S, M, L) with the clear M tips on the headphones. Other accessories include a pair of tweezers (which are actually not very useful), a screw-on metal hard case that seemed very sturdy, an airplane adapter, cleaning tool, and - most importantly - the keychain with all the filers and nozzles.
    The FLC8S are not black as suggested by a lot of pictures online; instead, they are slightly blue in color.The IEMs themselves are surprisingly small. Even though they look plasticky, they seem well-made. Another bonus is the removable cables (I have not tried pulling them out yet - a brave soul who gets these headphones can try!). The cable's braided and seems pretty sturdy, even though the upper part seems a bit thin. It's slightly bouncy and microphonic, but I don't find it a major problem for me. One thing I'd like to mention is the memory wire portion, which created some troubles for me initially - I've been spoiled by the nice cables on the Westone 4 and thus found the memory wire pesky, as it prevented me from getting a secure over-the-ear fit and the headphones would move easily when I was walking. Eventually, though, I got used to it. Another problem is the non-angled nozzles, which may be a problem for some people. I personally found it fine but my friend did complain that it was slightly uncomfortable when he put them on, so that's also something to consider. Besides these two minor points, though, the fit is very nice, due to the small form factor. They're also very light, which helps a lot in securing the headphones. 
    A major selling point is the tunability of these headphones - the nozzles are interchangeable, and there are two bass/sub-bass ports on the housing. It's surprisingly simple to switch, although I do recommend working on a clean surface - I've already nearly lost a few parts during the switching. Switching does require a (fairly) steady hand, but it's not a big issue - I believe most people won't have problems. The filter/port/nozzle container (whatever you want to call it) is tiny and the organization isn't exactly very elegant, but it gets the job done in a compact way. The container's also pretty portable and fits into the metal case. Overall, I'm surprised at the build quality of this - its tiny form factor and sturdy housing is pretty nice. *inserts gif of an excited child opening a package* 
    Some pictures of the FLC8S ft. Macbook Air - sorry if they're not of very good quality: 
    There is a slightly metallic, bluish tint to the headphones. 
    The sub-bass port is on the inner surface of the housing (the red dot - high sub-bass port). From the top you can see the golden nozzles I'm currently using.
    The memory wire (top part) isn't exactly the most user-friendly, but the braided cables are rather thin and light (and sometimes bouncy). 
    The tuning container/keychain with all the nozzles and filters I'm not using. The container isn't very elegant but it fits everything in a small space.
    The dark grey dot on the housing is the bass tuning port (set to mid). The nozzles aren't angled, which may be a problem for some people.
    Sound Quality
    Since there are 36 possible sound tunings I'm not going to talk about all of them. After some experimenting, though, I've found a few pairings that I liked a lot. I'll briefly talk about those, as well as the overall sonic character of these gems. 
    It's hard to discuss these without first talking about the tuning. So apparently there are 4 nozzles which influence the mids and the highs, 3 bass tuning filters, and 3 sub-bass tuning filers. I think everyone's going to stop reading this (and pass up on these things... [​IMG]) if I discuss all these nozzles in detail, so I'll just stop obsessing over them now. I did give all of the combinations a try and eventually settled on a few that I found was wonderful for the genres of music I listen to. 
    Pairing 1: Red (High sub-bass) - Grey (med bass) - Gold (high mids/med treble) 
    Pairing 2: Red (High sub-bass) - Grey/Black (med bass/high bass) - Black (med mids(?!)/mid treble)
    Pairing 3: Black (Med sub-bass) - Grey (med bass) - Green (med mids/high treble)
    First Impressions: 
    Geez, these things are good. Straight out of the box they sounded so smooth and clear at the same time already. The soundstage was spacious, vocals were airy, bass was there but not too much... Compared to the Westone 4s these sound very, very clear. The detail is really nice - I could hear the smallest breath noise from EXID - and vocals seem very natural. Treble seemed slightly brighter than what I'd gotten used to on the Westone 4, but in a good way. It was clearer, a bit more shimmery but not to the point of being sibilant or intolerable. Seems like we've got something glorious in the making here....
    As I've said, I'm pretty sensitive to sibilance. By all accounts this isn't a pair of super bright headphones, even though with the green or blue nozzle you could make it border on burning your ears out. With the less treble-happy tunings, however, the treble is very clear and effortless - it's just there. Even when I used the green nozzles, with the right tuning I could tolerate the slight sibilance of the pop tracks. In orchestral music, especially, the treble is bright, but not overly so - just enough that you can maintain an excellent balance between detail and smoothness. Cymbal clashes sound very lively and energetic, with just the right amount of sparkle. It's a pretty good balance. With the more treble-happy nozzles, there's more detail (and sibilance), but with the right tuning and right tracks it can make the orchestral pieces sound incredibly detailed. The airiness also makes the treble extremely natural - and this isn't just limited to the green nozzles, it's the same for the gold and black nozzles.
    Warning: with the wrong tuning using the green nozzles these can be extremely sibilant. You have been warned. 
    I enjoy the mids immensely on the FLC8S, especially with the gold nozzle. Vocals seem very airy and detailed; the mezzo-soprano's voice was captured perfectly - it feels like I'm listening to a live opera performance. There's probably no way to screw the mids up on this thing - they are that good. Nuff said on them.
    Ah, the magical red filter. 
    Orchestral music just comes to life here - the bass isn't exactly linear like reference flat headphones (Brainwavz B2, looking at you) - slightly more exciting than that. It adds another dimension to the music, there's the constant presence of the cellos and double basses; yet they don't overwhelm the piece - they're just there, like everything else. The sub-bass extends pretty low, with a nice rumble and I don't really notice any mid-bass hump - probably because I'm using the mid bass ports - and so the bass is very strictly controlled the whole way. It's also pretty quick - EDM lovers will probably be satisfied with how the bass handle your music. I'm really happy with how these handle the bass region - they're so in control, so authoritative when I give it my attention, yet unassuming when I need it to be. Probably my favorite part of the whole spectrum.
    Across the spectrum and other notes:
    These are incredibly coherent - @Flcforrestwei has done a really good job doing the crossover of drivers. It's hard to characterize them by a single sonic signature, but in general I'd say they are rather balanced, and slightly skewed towards either the cold side (with the green nozzles) or warm side (higher bass). There's no noticeable hump in any region as far as I'm concerned, and they are rather spacious no matter what you do to them. The soundstage is very wide, with pretty accurate positioning, and there is no veil even if you crank the bass up. They also don't have that artificial timbre that I sometimes get from other headphones (especially some IEMs with metal housing) - everything sounds very natural, and I noticed that especially with the mids, they just seem so effortlessly smooth yet detailed. It's a wonderful feeling.
    I feel like the difference between the nozzles/ports are very noticeable and they really do a lot to change the sound, but ultimately the whole sound signature is still built on airiness, detail retrieval and great control - and no tuning can change that. Which is a good thing. [​IMG]
    My favorite pairings... 
    Combo 1: Red - Grey - Gold 
    This is what I use for a lot of vocal-focused songs. I feel like it gives me enough bass rumble and excitement to pump up the piece, yet it doesn't overpower the vocals. With the gold nozzles, vocals are prominent, smooth and airy - very very realistic, as if I'm watching a live performance. I feel like the "magical red filter" just helps improve everything - bass presence, warmth, balance, etc. Using the black filter kind of takes away from the whole excitement. 
    Combo 2: Red - Grey/Black - Black
    Grey's a more neutral choice, and black's a bass cannon (well, not really, but on the scale of FLC8S...) 
    I usually listen to pop songs with this combo, mainly because it's the most versatile and balanced across all spectrums. It doesn't provide any emphasis on any region and everything is smooth across the spectrum - no humps, no peaks - and even pieces that aren't mastered that well sound fairly musical. Again, the red filter does its magical job again by up-ing the oomph - the thumping when listening to dance pop music is incredible. When I use the black ports instead of the grey ones, the FLC8S instantly becomes a more bass-heavy headphone, akin to the Westones in quantity, but exhibiting more control in my opinion. 
    And you know what the best part is? It still doesn't overpower the other parts of the spectrum. 
    Combo 3: Black - Grey - Green
    Pretty bright combo - I thought it wasn't my thing. I was wrong. 
    Listen to a vocal piece with this and the green nozzle absolutely nails the high notes. Listen to an orchestral piece (and maybe using the "magical red filter") and hear the violins come to life, performing right in front of you. Although I'm usually not a fan of bright treble I absolutely love this combo for classical music - somehow the treble manages to be airy, detailed, with slight sibilance but tolerable by my standards. It gives me so much more detail to look for during orchestral pieces - the attack, the cymbals crashing, the balance... I'm amazed at what these little IEMs can pull off. It's bound to be something a treblehead will enjoy, listening to all the detail in there. 
    Even though they are really, really easy to drive - already sounds pretty well straight out of G4 and a bit of improvement with the Dragonfly - they scale up pretty well. On my desktop setup, using the O2 enables me to hear even more detail on the same piece, and everything is just tightened up a tad bit more. Not a huge improvement, but definitely noticeable. 
    I think airy and detailed seems to be the common theme between all the different sound signatures here - I feel like the FLC8S are an incredibly versatile pair of IEMs with its foundation built on the two qualities that I cherish most. For me, these are end-game IEMs - it does everything so well that I don't find myself reaching for other pairs of IEMs in my collection when I'm using these. Everything combined, the FLC8S are an amazing package despite the tiny, tiny problems in terms of design - I couldn't have asked for more in any pair of IEMs, albeit this pair priced at a mere $250 (or $310). Considering their asking price, I feel like these should receive more attention - even if they only had one sound signature - and everyone should have the opportunity to experience what they pack in such a tiny form factor. 
    1. View previous replies...
    2. RollsRoys
      Thanks for the review, really interesting hybrid earphones 
      RollsRoys, Dec 11, 2015
    3. karanehir35
      I am pleased also FLC 8s.
      karanehir35, Dec 13, 2015
    4. pedronet
      Great review :) i hope to get a chance to listen to them one day
      pedronet, Jun 17, 2016
  3. HiFiChris
    "36 Faces of a Modder's and Tweaker's Delight" -or- "Flagship Performance for a Mid-Fi Price"
    Written by HiFiChris
    Published Mar 29, 2016
    Pros - that sweet & detailed midrange!, instrument separation, versatility, build quality, bass speed, coherency, good resolution
    Cons - tweezers useless even when correctly operated (better use your fingernails), upper treble refinement could be slightly better, microphonic stock cable


    There are various universal in-ears out there that feature replaceable sound tuning filters that guarantee for a (sometimes more, sometimes less significant) sound alteration to one’s personal preference, but there hasn’t been any that allows for 36 filter combinations – well, at least until now, as the FLC Technology FLC8s does indeed offer three filter groups that can be combined to 36 possible filter combinations.
    FLC Technology (flctechnology.com) is a Chinese audio company that was founded in 2011 by Forrest Wei. The letters F, L and C (pronounced “Fu Lai Si”) by the way stand for “Happiness/Fortune comes here”. Before FLC, Forrest has worked as engineer at various renowned audio companies for many years (his vita contains Ultimate Ears, Jabra, MWM Acoustics and Harman), and this experience can be indeed heard with his latest creation, the FLC8s. Before this model, FLC Technology offered a custom-moulded hybrid in-ear that offered the same patented filter technology.
    What’s quite special about the FLC8s is that unlike many other hybrid in-ears which feature a coaxial driver design layout where the midrange/high frequency drivers sit in front of the dynamic woofer and end in a large single-bore nozzle, Forrest’s creation features an independent dual-bore design that merges before the nozzle, which allows for the individual tuning of the different driver designs.

    A sample of the FLC8s In-Ears was provided to me free of charge for the purpose of an honest evaluation. My hearty thanks go to FLC Technology’s Forrest Wei and Lend Me UR Ears for this opportunity.

    Technical Specifications:

    Price: ~ $349 (http://www.lendmeurears.com/flc8s-red/)
    Sensitivity: 107 dB/mW @ 1000 Hz
    Frequency Response: 20 Hz – 20 kHz
    Drivers: 1x 8.6 mm dynamic, 2x Balanced Armature
    Impedance: 11 Ohms
    Cable Length: 1.2 m

    About Hybrid In-Ears:

    As you can read from the technical specifications, the FLC8s is a little different from most In-Ears and doesn’t only use dynamic or Balanced Armature transducers, but combines both in one shell.

    Most In-Ears use dynamic transducers for audio playback which have the advantage of covering the whole audible spectrum and achieving a strong bass emphasis without much effort. Valuable dynamic drivers are often said to have a more bodied and musical bass that has a more soft impact and decay and lacks of the analytical character that BA transducers are known for. On the downside, in contrast to headphones with other driver principles, dynamic transducers often have a lower resolution.

    Higher-priced and professional IEMs mostly use Balanced Armature transducers, which usually have got a higher resolution than dynamic drivers, are faster, more precise and have got the better high-level stability, which is important for stage musicians that often require higher than average listening levels. On the downside, it is quite hard to cover the whole audible spectrum with just a single BA transducer and strongly emphasised bass is only possible with multiple or big drivers. Some people also find In-Ears with BA transducers to sound too analytical, clinical or cold (in several active years in a German audio community where I wrote multiple reviews, gave dozens of purchase advice and help, from time to time I heard people that got into BA earphones for the first time using these attributes for describing BA earphones, especially their lower frequencies).

    Hybrid IEMs unite the positive aspects of both driver principles and use one dynamic transducer for lows reproduction and at least one BA driver for covering mids and highs, wherefore the often as “musical” described bass character remains and the BA transducers add resolution and precision to the mids and highs – and that’s what the FLC8s does with its technology. It is addressed to those people who perceive the clinically-fast character of BA transducers as unnatural, but want to keep the mids’ and highs’ resolution, speed and precision.

    Delivery Content:

    For me, a valuable product deserves an appropriate packaging, and the FLC definitely does not disappoint in this regard.
    On the outside, the slightly larger, surprisingly heavy and sturdy box is rather plain looking with its pale sand colour and the silver logos, but offers a quite interesting and well-thought, unique way to open it, whereon the arrow with the “open here” text in the lower left corner already gives a hint. The front (and all ensuing sides that can be opened) is magnetically attached and can be folded up, kind of like a chest. Then, the in-ears which are embedded in blue foam become visible. Pushing on the foam where the black arrow with the “press to open” text is located, it can be taken out; inside this upper layer are large plastic tweezers and a quick-start guide that explains the filters and gives some combination examples.
    On the front, another arrow with “open here” text points to the left side which can be swung open as well, then the whole top layer with the foam can be flipped away to the right side, which is pretty cool in my opinion. Inside the second layer, one can see the blue foam again which embeds the carrying case for the in-ears as well as the small cylinder that contains the filters.
    In a plastic bag are a 6.35 to 3.5 mm adapter, a cleaning tool, an airplane adapter, four pairs of black silicone tips, three pairs of white silicone tips (the fourth pair of the white tips is already installed) as well as finally six spare tuning filters for the bass and sub-bass.

    IMG_20160208_183016_hdr.jpg   IMG_20160208_183027_hdr.jpg
    IMG_20160208_183058.jpg   IMG_20160208_183149_hdr.jpg
    IMG_20160208_183215_hdr.jpg   IMG_20160208_183256.jpg
    IMG_20160208_183318_hdr.jpg   IMG_20160208_183402.jpg
    IMG_20160208_183415.jpg   IMG_20160208_184337.jpg
    IMG_20160208_184454.jpg   IMG_20160208_184704_hdr.jpg
    IMG_20160208_184835.jpg   IMG_20160208_184852.jpg

    Looks, Feels, Build Quality:

    The in-ears are available in two colours (red or blue), quite small and made of plastic, which I wouldn’t have noticed if I hadn’t randomly read it somewhere on the internet, as I really thought FLC8s’ bodies were made of metal, as they feel very sturdy, are extremely well varnished (wherefore they appear like they were made of metal) and the used plastic is of very high quality; additionally no glue residues can be found at the part where both body halves are joint.
    On the inside are the holes for the sub-bass filters; also on the inside are the side-markers on the bodies as well as on the cable connectors. On the outside, the holes for the bass filters can be found. The filters for the midrange and treble are made of metal and screwed into the nozzle.
    Except for the mids/highs filters, the other rubber/plastic filters for the lows are really small and easy to loose, wherefore changing them should be best done with steady hands and when sitting.

    IMG_20160208_185520.jpg   IMG_20160208_190331.jpg

    The cable is of dark blue colour, replaceable and features the same 2-pin connector system as the Ultimate Ears Triple.Fi 10 (0.75 mm pins). Although it has got the typical, valuable, twisted quad-litz style from the professional audio sector, it is a bit springy (though at the same time quite flexible, nonetheless not as flexible as other twisted cables) and has a cable cinch (chin slider) that sits enormously tight so that it can only be moved with much effort. To top it all, it is quite microphonic, but more about that in the next “Comfort, Isolation” paragraph.

    IMG_20160208_185038.jpg   IMG_20160208_185104.jpg
    IMG_20160208_185118.jpg   IMG_20160208_190342_hdr.jpg

    The carrying case is made of metal and I quite like it: although it may not be best suitable for fully portable use, it looks and feels very valuable, massive and has got precisely cut threads. The outside has a really beautiful gunmetal-blue finish and is completely bolstered with fabric on the inside (which is in my opinion a must for every in-ear case – I can’t stand bare plastic or metal on the inside of a protection case), so the in-ears are well protected.
    The small blue cylinder with the keychain for the tuning filters strongly reminds me of the one that came with my Shure SE846, however the blue one of the FLC8s has got the benefit that the filter elements are stuck into a block of rubber, so it is less easy to lose the seven pairs which are inside (the three others are in the in-ears themselves).

    IMG_20160208_185006.jpg   IMG_20160208_185449.jpg
    IMG_20160208_185917_hdr.jpg   IMG_20160208_190205_hdr.jpg

    Comfort, Isolation:

    The in-ears are actually quite small and are easy to insert into the ears; then they sit very securely and comfortably, whereto the cable connector’s angle also plays a leading role. With my large ears, I have almost never problems with the fit of in-ears anyway, so these sit extremely well in my ears, too – but even most people with (very) small ears should be able to get a really good fit and comfort with the FLC8s.
    Like most models in this price range, the in-ears are supposed to be worn with the cables over the ears which usually improves fit as well as comfort and drastically reduces microphonics – unfortunately the latter is not true in this case, as FLC8s’ cable is quite microphonic for a model of its kind and transports cable noise with every small touch or movement – pity! Tightening the cable cinch behind the head and then guiding the cable over the shoulder, microphonics are slightly reduced, however still obviously stronger than they are supposed to be.

    Isolation is better than average, however not as strong as with fully closed in-ears. Nonetheless, exterior noise is blocked out somewhat more than with many vented in-ears.


    For testing, the source devices I used were the iBasso DX90, Leckerton UHA-6S.MKII, FiiO X3 (first generation) as well as LH Labs Geek Out IEM 100. Music material was mainly stored in FLAC format (lossless rips of my CDs in 16 Bit/44.1 kHz), but I also used Hi-Res, DSD and some MP3 files.
    I used the largest included white silicone tips for listening.


    The major question I had to deal with while testing was “how do I best describe an in-ear that allows for up to 36 different sound signatures by using different filter configurations?”.
    My decision was then to first describe all filters and their effect individually and then finally to give a couple of different sound descriptions of a few filter combinations.

    Overall there are 10 pairs of filters that can be summarised in three groups that alter other frequency ranges, wherefore up to 36 different sound characteristics are possible (3 x 3 x 4 = 36). Included are three pairs for the sub-bass (“ULF”) that are inserted on the inner side of the bodies, three pairs for the bass (“LF”) that are inserted on the outside as well as four pairs that are screwed into the nozzle and have an effect on the midrange and treble (“MF/HF”).

    The different filters listed in tabular form:
    Clear = Minimum
    Clear = Minimum
    Blue = Minimum HF
    Grey = Medium
    Grey = Medium
    Gunmetal = Medium MF & HF
    Red = Maximum
    Black = Maximum
    Green = Medium MF & Maximum HF
    Gold = Maximum MF & Medium HF

    Ensuing are a few frequency response measurements of the different filters and the effect that they have on the frequency response. The plots’ colours also represent the filters’ colours.
    Please note that the plots weren’t recorded with professional equipment but with my Vibro Veritas coupler that was pseudo-calibrated to more or less match a real IEC 711 coupler’s response with applied diffuse-field target, hence the results shouldn’t be regarded as absolute values but rather as a rough comparison and for getting a general idea of the sound. Especially at 3, 6 and 9 kHz, there are sometimes greater deviations from professional plots, but for a general, rough comparison between various in-ears and filters, the results are sufficient.

    (ULF Filter  I  Grey  I  Gold)


    (Grey  I  LF Filter  I  Gold)


    (Grey  I  Grey  I  MF/HF Filter)


    With these in-ears, the focus lays obviously on the ability of individual sound adjustment with the help of the included filters that can form up to 36 (3 x 3 x 4) different combinations and sound signatures. For changing the filters, large plastic tweezers come included. For daily use, I found using my short fingernails (less than 0.5 mm) to be more helpful for changing the filters, as that gave me better control over the filigree things and they also slipped out of my hands way less often, nonetheless it is quite a fiddling to get them in and out. Probably smaller, rubberised tweezers would be more practical.

    What follows now is a small selection of different filter combinations that are displayed in this form: [ULF]/[LF]/[MF/HF]
    01: Grey/Grey/Gold:
    This is the filter combination the in-ears arrived with.
    The sound signature of it goes like this: down from 500 Hz, the bass emphasis which raises very evenly and flat begins and forms its climax which is about 6 dB north of neutral sound (Etymotic ER-4S) below 100 Hz, in the midbass; sub- and midbass are even plus plane and also in the sub-bass below 30 Hz, level doesn’t roll off. Given that, the bass is present, however definitely not over-accentuated and fits in coherently, as there is no unnecessary fundamental tone bloom.
    The mids around 1 kHz are broad-banded emphasised, with a somewhat greater focus on the upper mids, bringing out (especially female) vocals’ details a bit more, but also slightly accentuating sibilants if the recording isn’t super clean. Tonally, the mids are mostly correct in my ears, with just a minimal tendency to brightness (for reference, DN-2000J’s mids are minimally brighter than FLC8s’ in my ears). From the presence area above 2 kHz on, level drops evenly and forms a greater recession around 5 kHz which guarantees for good long-term listenability without fatigue and with unobtrusive mids; that’s why many in-ears show a somewhat similarly distinctive dip around 5 kHz, for example the Fischer Amps FA-3E whose dip in the middle treble is about identical to FLC8s’ (a good thing is that it isn’t as distinctive as W4R’s dip which adds a bit too much smoothness and relaxedness to the highs and mids with a tendency to mugginess; FLC8s’ middle treble character is just “normal with a somewhat relaxed, non-obtrusive character” and clean plus detailed). From 6.5 kHz on, level starts increasing again and forms a peak in the upper treble at 8 kHz which is marginally above the ground-line and not annoying at all. Super treble extension is still good, with even level up to 12 kHz and an even roll-off from there on. Subtle “glare” above 10 kHz is still audible and I actually don’t miss anything in terms of treble extension, although there are some multi-BA in-ears that reach even higher in the treble before the roll-off begins.
    For daily use, this kind of tuning appeared to be quite enjoyable – the bass is somewhat accentuated but not too much to become obtrusive, but is just there to add a little weight, vocals come through very clearly due to the moderate emphasis and sound very clean, the somewhat recessed level in the middle treble guarantees for a good long-term listenability without fatigue and the slight emphasis in the upper treble is just lightly noticeable, though percussions sound slightly brighter.


     02: Grey/Clear/Blue:
    With this filter combination, I would describe the sound as quite neutral with smooth, dark treble.
    The bass is slightly more present than with a Clear/Clear/MF-HF combination (ca. 2 dB north of neutral below 80 Hz), though the benefit is that it doesn’t roll off in the sub-bass with this filter combination. Here, the mids show a slight broad-banded emphasis, too, though there is no emphasis in the upper midrange and vocals are on the darker as well as more relaxed side, without any signs of sibilance. The middle treble is somewhat in the background as well, though even a bit more than with the gold MF/HF filter, so the impression of a smooth, relaxed midrange and treble is even stronger (for my personal preference, it is even slightly too relaxed and heads into Westone W4R’s smoothness in the upper frequencies). The upper treble is now also clearly in the background and darkens the sound.
    If you love a balanced bass and midrange with a downwards-slope in the highs, this tuning might be for you.

    03: Red/Black/Blue:
    With this filter combination, sound is an evenly down-sloping curve from the sub-bass to the upper treble and slightly reminds me of the reference curve for car-hi-fi.
    Again, the emphasis in the lows starts at around 500 Hz and then increases very evenly with a straight line, without any hump, towards sub-bass where level is about 9.5 dB north of neutral at 30 Hz. The midbass is a bit less present and so is the upper bass with about 5.5 dB, with an evenly decreasing fundamental tone area. As a result of this characteristic, the bass fits in nicely and unobtrusively, without too much upper bass kick or fundamental bloom, as the emphasis is mainly in the mid- and sub-bass. Accordingly, the lows also commendably stay away from the mids.
    The midrange is not slightly emphasised anymore here with this filter configuration and is, just like with the previous Grey/Clear/Blue filter combination, somewhat on the dark, relaxed side. Treble is identical to the previous tuning.
    For a smooth, relaxed, bass-emphasised tuning with “cellar rumble”, this tuning is well-suited.

    04: Red/Grey/Gold:
    This filter combination focusses more on the sub-bass, along with bringing a detailed midrange and correct treble into the game.
    The lows more or less resemble the previous Red/Black/Blue filter combination, however with this Red/Grey/Gold configuration, the sub-bass shows to advantage more as both the root as well as upper bass are slightly less present. The bass kicks a bit less and concentrates more on the “cellar rumble”.
    The mids around 1 kHz are just very minimally lifted and sound tonally correct in my ears.
    The middle treble is about identically in the background as with the first (Grey/Grey/Gold) combination and gives some smoothness and good long-term listenability without fatigue. The upper treble sounds quite natural and as well as not emphasised, but straight to the point.
    For a sound with balanced midrange and treble plus elevated sub-bass with less upper bass and fundamental tone, this filter combination works very well.

    05: Red/Black/Green:
    With this filter combination, the sound of the in-ears follows a v-shape.
    The bass is quite identical with the third filter configuration (Red/Black/Blue) and expresses itself with a somewhat emphasised “regular” low-range with upper bass and fundamental tone area, with the greatest focus being in the sub-bass.
    The mids around 1 kHz are just very marginally emphasised and in total view, when incorporating lows and highs, vocals are even a bit in the background and also sound somewhat thin, however neither hollow nor low resolving.
    The middle treble is audible less in the background with the green filter; the upper treble at 8 kHz shows a distinct peak which is however still humane and not too sizzling or piercing as long as one isn’t listening at very loud volume levels. Nonetheless, sibilance is more emphasised and some recordings get the tendency to be a bit annoying and hot.
    For lovers of v-shaped signatures, this filter combination might be well-suited.

    06: Clear/Clear/Gold:
    This filter combination is one of the recommended in the quick-start guide and is labelled as “Vocal” – for reason, as it really is a signature that focusses on voices.
    The bass is rather lean and mostly neutral, at least in the upper midbass, upper bass as well as lower and upper root area. In the middle fundamental tone, there is a minor emphasis; the bass starts evenly rolling off from about 50 Hz.
    The mids are in the foreground with this tuning, with a preference of the upper midrange, wherefore this filter combination is well-suited for female vocals. Male singers however sound a bit thin.
    The treble is identical to the first (Grey/Grey/Gold) tuning.
    For tracks with mainly female singers, this tuning is recommendable if one wants to bring out the voices some more.

    07: Grey/Clear/Gunmetal:
    This is the filter combination that I see as reference tuning for the FLC8s, and as somebody who loves neutral sound and sees the Etymotic ER-4s as the best example of how neutral tonality should be (the ER-4S is even closer to ideal neutrality than my custom-moulded UERM), I can also say that the FLC sounds pretty neutral with this filter combination and comes quite close to ER-4S’ tonal tuning.
    Upper bass, midbass plus the lower fundamental tone are very marginally more present than with a Clear/Clear/Gunmetal combination which however suffers from a moderate sub-bass roll-off, wherefore I see the Grey/Clear/Gunmetal filter combination as the more reference-like. Otherwise sound is free from any unnecessary warmth and the bass is very even, “flat”, without real emphasis.
    The mids are pretty spot-on and tonally correct in my ears, without colouration.
    The middle treble is somewhat in the background as well, however very slightly less than with the gold filter and therefore seems a bit less relaxed. With this filter combination, the upper treble is also just very slightly, though inconspicuously above the ground-line.
    For a rather sterile, very neutral sound, this filter combination is quite ideal (and I personally love it).

    For the following comparisons, I used the first and seventh filter combination most of the time.


    The resolution capabilities of this in-ear are simply stunningly high for the price and I go that far to say that the FLC8s can compete with my UERM in the midrange and treble department without problems. In the highs, the UE is very slightly more differentiated plus refined and also a bit more realistic despite its peak (in comparison, the FLC sounds slightly constrained/dull in the upper treble), but in the mids both in-ears are about on-par and honestly speaking the FLC8s sounds even more detailed in the vocal area, as it reveals more minute details while sounding very easy-going, precise and natural. Even after about two months of almost daily use, these in-ears still manage to positively impress me with their very good technical capabilities and detailed, silky midrange. Tiny details in the treble and mids are no problem for the FLC8s and fine details are presented and revealed in a very easy-going, natural way. I guess I don’t even have to mention that speech intelligibility is extremely high, as that should be clear from the context.
    In the lows, it looks a bit different, but that is simply because of the different driver types: although FLC8s’ bass is very fast and precise, it doesn’t reach the precision, control and details of UERM’s Balanced Armature driver when very fast and complex tracks are being played. FLC8s’ bass character is quite typical for a (really good) dynamic driver and it is not too hard to tell that it is no BA woofer, but on the other hand, this dynamic woofer driver is very detailed on its own and sometimes, especially with less complex and rather slow music, it is quite difficult to say whether it is a dynamic or BA driver, although the bass doesn’t stand in the room straight to the point but is a bit more space-filling.
    What Forrest Wei has created hare is a really detailed, technically very capable and brilliant in-ear that has enormous cohesion between the three drivers which harmonise perfectly together, so that the dynamic driver fits in perfectly and doesn’t appear even at the slightest negatively but just somewhat more corporeal and less “sterile”.


    The sole area where the FLC8s could yet fail is the soundstage, but it also copes with this discipline with ease: FLC8s’ soundstage is quite large in terms of lateral expansion and about comparable with the one of my UERM. Therefore, width is also somewhat wider than DN-2000J’s stage (though not by much). There is also a good amount of depth, though it is just about one quarter less distinct than width, wherefore soundstage isn’t as deep/almost bottomless like the DUNU’s or UE’s. When it is about three-dimensional presentation and naturalness, the FLC leaves a very positive impression and sounds harmonious.
    Regarding instrument separation and spatial precision, the in-ears are technically really strong, as single elements, even if they are yet so small, are super precisely separated – almost as precisely as with the UERM. And as a result, the FLC8s even manages to separate and place instruments slightly more precisely than the DN-2000J which already does a really good job here.


    In Comparison with other Hybrid In-Ears with three-Drivers-three-Ways-Configuration:

    Oriveti Primacy:
    The Oriveti Primacy is a really good and convincing hybrid in-ear with a smooth yet detailed and (in a very positive way) non-exciting sound as well as superb build quality. When it is about sonic strengths, the Primacy comes very close to the DN-2000J, which speaks for its sound quality. However, the FLC8s manages to unveil even more details in the midrange and treble, in addition FLC’s dynamic woofer is even better and more cohesively integrated to the system as it is almost just as good as its two brilliant BA drivers for the mids/highs (Primacy’s lows are very slightly less detailed than its mids and highs although sound is harmonious and coherent, too).
    FLC8s’ soundstage is a bit wider than Oriveti’s and has especially got somewhat more depth. In terms of instrument separation, -placement as well as spatial precision, the FLC is also the winner.

    DUNU DN_2000J:
    The DN-2000J is an extremely good in-ear and convinces inter alia with its special bass which is both very fast and precise as well as tactile and has a gorgeous body at the same time (its lows’ qualities are quite similar to my Audeze LCD-X’s). On top, midrange and treble resolution are excellent.
    Well, the FLC8s reveals even a bit more details than the DUNU and also has got a minimally faster bass which is more arid too, although DN-2000J’s is already really good for a hybrid in-ear. What the FLC however doesn’t adopt is DUNU’s woofer’s special character which is albeit something very unique for itself – in exchange, FLC8s is overall sonically and technically the somewhat better and slightly more refined, detailed in-ear.
    FLC8s’ soundstage is a bit wider than DUNU’s, however less deep. In terms of spatial presentation and instrument separation, the FLC is somewhat more precise, with instruments that are very cleanly placed and sharply separated from each other – even more than DN-2000J’s.

    UPQ Q-music QE80 (OEM Version of the Fidue A83):
    Without any doubt, the FLC8s is the more versatile IEM with its theoretically possible 36 different tonal tunings, but will always have less fundamental warmth than the QE80.
    The FLC, of which I think is overall very slightly better than the DUNU, also surpasses the UPQ. The FLC8s has got the faster and more arid lows than the QE80, which on the other hand puts out the nicer bass body (this however goes at the expense of speed). When it is about resolution, the FLC is somewhat better as well, even in the midrange.
    Solely QE80’s upper treble sounds a bit more natural and realistic as it is more broad-banded.
    The FLC’s soundstage is slightly wider, with about identical depth. In terms of spatial precision, the in-ear with 36 faces wins as well.
    Victory (however not a big one) of the FLC8s in every aspect expect for upper treble naturalness.


    The FLC8s is not only an extremely good hybrid in-ear but also definitely a hybrid flagship. The in-ears are very convincing with their precision, soundstage, resolution (especially in the midrange – vocals sound so clear, detailed and realistic that they even slightly beat my UERM’s) as well as versatility. Surely the knowledge of having 36 potential sound signatures is really cool, however realistically seen, one will more likely have up to four filter combinations that are probably slightly tweaked from time to time. One also has to be careful with the any filigree filters, as they can be lost easily given how small they are – in this regard the FLC8s is more an in-ear for enthusiasts than a product that is suitable for the masses, but I personally find it good that way as it shows how much is technically possible with the various filters.
    What unfortunately doesn’t fit to the sound which can be almost seen as being on the same level as the UERM is the cable which is very microphonic for a model of its kind.

    Sonically this in-ear scores 5 out of 5 stars with brilliant ease – with a 70%-sound-to-30%-rest-weighting however, the FLC8s “only” manages to score 4.5 out of 5 stars, which is quite sad, as with a less microphonic but more flexible cable, this would be unquestionably a 5/5 product. But even so, the in-ears get a really distinct recommendation for their sonic qualities and two thumbs up.
      canali, Raketen, leobigfield and 14 others like this.
    1. View previous replies...
    2. raze94
      Thank you very much for the reply. It really is a tough choice especially after reading up on the Oriveti. I checked the website for the FLC8s and I assumed it was US dollar. I guess I cant go wrong with any of those?
      raze94, Aug 7, 2016
    3. HiFiChris
      Ah, the price you mentioned is in SGD on the LMUE website, you have to switch it to USD in the upper right section of the page.
      HiFiChris, Aug 7, 2016
    4. raze94
      Ok thanks for that bud. It makes a huge difference in price.
      raze94, Aug 7, 2016
  4. nmatheis
    FLC8S: An Undiscovered Gem!
    Written by nmatheis
    Published Jan 11, 2016
    Pros - High-quality, highly-customizable sound. Small. Ergonomic. Built well. Detachable cables.
    Cons - Microphonics. Overly tight cinch. Limited tip choices. Very small tuning filters.


    Image courtesy of FLC



    Hi guys. I discovered a real gem of an IEM in 2015, the excellent FLC8S. Out of all the IEM I tried in 2015, this is the one that most caught my attention and has gotten a disproportionate amor of ear time. How did this all come about? Well, I was chilling out, jamming to some music one day when I noticed an email in my inbox from Teo over at LMUE (Lend Me Ur Ears). In the email, Teo asked if I'd like to check out the FLC8S because he though they were a great IEM that deserved more attention. I didn't really know anything about them, so I started looking around to see what these were about. One of the first things that popped up was a stellar review of the original FLC8 by Joker over at The Headphone List (LINK). He gave them a solid recommendation, and I learned that they were the most customizeable IEM I've ever heard of. If you've followed my reviews, you might remember that I've reviewed a few customizable IEM recently. Those were the RHA T20 (LINK) and the Torque Audio t096z (LINK). I also own the Trinity Delta. While the RHA T20 and Trinity Delta offer a few different "flavors" of the same basic sound signature, the Torque Audio t096z offers six unique sound signatures. They are all very nice IEM, and I enjoy listening to them all. Anyways, back to FLC8S. They have 36, count 'em, 36 different tuning options. That sounded really cool, so I shot an email back to Teo and told him that I'd love to check them out. Well, long story short, I fell in love with them. I've shared them around a bit, and everyone I've let listen to them has also been very impressed with them. I gave them to a self-pronounced treble-head and bass-head at a local mini-meet, and both said they were amazing. I didn't even change the tuning to accommodate their preferences. I turned a couple of my fellow Head-Fi buddies onto them, and they both agree that these are right at the top of all the IEM they've listened to in 2015. Most recently, I let @Paulus XII in on them and wasn't surprised when they stole his heart, too. Yes folks, these are the real deal!
    Here's what FLC would like you to know about the FLC8S:
    FLC Technology is one of the earliest companies in China to explore the hybrid balance armature and dynamic driver technology. In 2011, it is the first company to launch a hybrids customs. The FLC 8S is the first universial hybrid balance armature and dynamic earphones by FLC technology. Due to FLC Technology's extensive experience in the hybrid technology, the FLC 8S features excellent cross over technology which creates a coherent sound between the dual balanced armature drivers and the dynamic drivers. 
    FLC 8S recongises that there is no one size fit all sound signature for all users. Hence, it is designed to be highly tuneable so that users can tune it according to their sound preference. While tuneable earphones are not new in the market, the FLC 8S represents the pinnacle of this technology as it allows for 36 variations of sound unlike most tuneable earphones which allows only 3 different sound signature at most. 
    The FLC 8S comes with improved built quality and comes with braided cables as compared to the FLC 8.
    I've also had a bit of back and forth with FLC's founder Forrest Wei (@Flcforrestwei) and learned a bit about him. Like most audio engineers, you've probably never heard of Forrest. Neither had I, but let me assure you that just like the FLC8S, he's is the real deal. Before starting FLC, he worked at Ultimate Ears at the time the venerable Triple-Fi 10 were being developed. He's also worked at Jabra and Harman. As you can see, he's been around the block. He started up FLC because he not only believes in hybrid IEM technology, he believes the sound should be customizeable to give every listener the right sound signature at the right time without buying several pairs of IEM. Besides FLC8S, Forrest also sells a CIEM version with the same 36 levels of custmization. Now that's unique! FLC also has a new line of single-crystal pure silver cables with all the connector choices you need. There's also a new flagship product under development. I've heard a bit about it and can't wait to give it a listen. Let me assure you it's going to be another amazing product from FLC. So there you go. Now you know a bit about Forrest Wei. We're lucky that he recently joined us on Head-Fi, hanging out with us FLC lovers over in the FLC8S thread. Thanks, Forrest!
    FLC8 & 8S Thread: LINK


    There is no financial incentive from FLC for writing this review.  I am in no way affiliated with FLC, and this is my honest opinion of the FLC8S.  I would like to thank FLC for giving me a chance to test drive the FLC8S, and I hope my feedback proves useful for my fellow Head-Fi members as well as for FLC.


    I'm a 43 year old father who loves music.  While I listen mostly to electronic and metal these days, I do listen to a wide variety of music - from electronic (Autechre, Boards of Canada) to modern/minimalist composition (John Cage, Philip Glass) to alternative rock (Flaming Lips, Radiohead) to jazz (John Coltrane and Miles Davis) to metal (Behemoth, King Diamond) to classic rock (Eagles, Rush).  
    I'm primarily a portable audio enthusiast. My portable music journey started with the venerable Sony Cassette Walkman and then progressed to portable CD players, minidisc recorders (still have my Sharp DR7), and finally on to DAPs like the Rio Karma, iRiver IHP-1xx, iPod 5.5, iPhones, and the newer crop of DAPs from Fiio and iBasso.
    Being a portable audio enthusiast, I typically listen with IEMs but am enjoying listening with full-size headphones more and more and tend to like u-shaped sound signatures, although I break out v-shaped IEM & HP from time to time for fun.
    As with a lot of people my age, I've got some hearing issues.  I've got mild tinnitus and suffer from allergies, which can affect hearing in my right ear.  I'll admit it, I'm not blessed with a pair of golden ears.  That said, I've been listening to portable gear for a long time and feel confident in assessing audio gear - just wanted to be transparent up front.



    1. Driver unit: 8.6 mm dynamic drivers+ dual balanced armature 
    2. Rated Impedance: 11 Ohm 
    3. Sensitivity: 93 dB/mW 
    4. Frequency response: 20Hz - 20KHz 
    5. Plug: 3.5mm gold-plated L-plug 
    6. Cable: 1.30m TPU cable
    7. Price: $350 (LMUE)



    As usual, I'll go over the packaging and accessories in pictorial format with a wrap at the end. 
    Looks like a plain box, right?
    Nope! The top cover folds back to reveal the FLC8S nestled in protective foam.
    Then that top layer slides out to the right to reveal the carry case and accessories keychain case. Cool!
    Here are all the goodies you get.
    Sorry about the stray tip in the pic...
    The unboxing experience is really fun. It felt like I just kept discovering more and more goodies stashed away inside. I recently got the Lotoo PAW Gold in for testing and noticed that the boxes are very similar. Turns out Forrest is a big fan of Lotoo DAPs!
    I like the nearly indestructible metal accessories holder and IEM case. These will most definitely keep your FLC and accessories safe and sound for a long, long time. I'm not sure I'll ever use the 1/4" and airplane adapters. Some might, though. Honestly, these would just end up in my stash of unused accessories. I'm sure you noticed the pair of tweezers were, right? That's weird. Tweezers packed in with a pair of IEM? What's that about? Well, they're supposed to help change the tiny tuning filters. I didn't find them very helpful, though. I ended up just using my fingernails to change the filters. Maybe some will need it, but not this guy. 
    The tips are basically the same shape, but the gray ones are softer and are the ones I preferred. And surprise, surprise, tip rolling has been a topic of discussion on the FLC thread. While I enjoy the sound with the stock gray tips, some don't like them and end up using third-party tips. Wide-bore double-flange seem popular. During my conversation with Forrest, I learned that the stock tips were chosen because they conveyed more detail. Even so, it'd be nice to see some different tip styles included to accommodate differences in ear anatomy and to allow users to further refine the sound to their taste.
    NOTE: The tuning filters are really small, so make sure to change them over something that can catch them if they fall.


    Again, I'll attack this section in pictorial format, commenting on what I like and what I think could be improved as I go.
    You can see a lot of the elements of the FLC8S in the picture up above. Lets start off with the earpieces. You can see all three types of modular tuning components for each earpiece that make the FLC8S so unique. On the left earpiece's inner face you can see the RED ULF (Ultra Low Frequency) tuning filter, while on the right earpiece's outer face you can see the GRAY LF (Low Frequency) tuning filter. You can also see the GUNMETAL MF (Mid Frequency) + HF (High Frequency) tuning nozzle. All of these are easy to remove. The tuning nozzles simply screw in. ULF and LF tuning filters are friction fit and fit in snugly. The ULF tuning filter is hard plastic and is the smallest of the tuning components. The LF tuning filter is made of silicone and is a bit bigger. It's easy to distinguish between these two, so you're not going to be putting the wrong tuning filter in the wrong port. Since they are quite small, please change these over the carry case or something similar so you don't lose them. FLC includes an extra of each ULF and F filter just in case you do lose one, though. And if you're really worried about losing them, you can purchase the tuning accessories keychain kit separately.
    You can also see the braided detachable cables with memory wire. All is color coordinated in a tasteful BLUE. Perhaps you can also tell from the picture that the FLC8S is pretty small. If not, I'll include an in-ear picture below to show you that they are indeed pretty darn small.
    FLC8S Schematic
    Here you can see all the tuning components, as well as the internals. I'll go over specifics for the different tuning choices available in the next section, but this gives you an idea of how flexible the FLC8S are in finding just the right sound for you.
    Cinch, Y-Splitter, L-Plug
    Good news, bad news time, people.
    Stock Cable
    Bad News: The stock cable is fairly springy and is microphonic, and the heat shrink tubing looks a bit shabby. Moreover, the cinch shrink tubing is so tight I had a very hard time moving it up the cable.  I let Forrest know this. He relayed this to the team, and they've made the cinch made a bit looser.
    Good news: The FLC8S comes with a high-quality OFC braided copper cable. With its coordinating blue color and heat shrink tubing, it has quite the boutique appearance. And I really like that it has an L-Plug that works with smartphone cases. 
    Original Cable
    Besides the stock cable, there's also the original FLC8 cable which is a standard black copper cable that is more supple and comes with a more typical, functional cinch and lacks memory wire. The copper is a bit lower quality, but it is a highly-ergonomic cable and allows the user to choose between wearing the FLC8S up or down and is lees prone to microphonics.
    Silver Cable
    The newest addition to the FLC lineup is the brand spanking new single-crystal pure-silver cable, which is very similar in construction so expect the same springiness and microphonics. I just got this, and the cinch on it is just right. Nice!
    FLC Cables: Original (top), Stock (bottom left), Silver (bottom right)
    NOTE: FLC8S use the same 2-Pin connector as the venerable UE TF10, so you'll have lots of aftermarket options should you choose to go that route.
    FLC8S in BLUE vs. RED
    In addition to the regular blue color, FLC8S are also available in a Limited Edition Red model. I think a mix n match model would be awesome!
    Worn Up
    Here they are worn up with the original FLC8 cable that doesn't have memory wire. Very comfortable for my ears.
    Worn Down
    With the original FLC8 cable, you can wear them down since it lacks memory wire. This isn't as comfortable for my ears, but my ears are a bit on the small side. I suspect those with anger ears will find it more comfortable. in any case, it's nice to have options, and I do find myself 
    Those of you who know me know I listen to a lot of electronic and metal. You might even know that I've been jamming a lot of classic rock lately, as well. I typically listen to music from Autechre, Behemoth, Bjork, Candlemass, Depeche Mode, The Eagles, Fleetwood Mac, Iron Maiden, King Diamond, New Order, Rush, and Sigur Ros during my time with new gear. I might throw in some hard bop jazz or modern minimalist composition every now and then. Just wanted to make sure you know what kind of music I listen to for context. Unlike some other reviewers, I don't keep to a strict playlist. Instead, I choose songs I know well and feel like listening to. I feel it's more organic that way. Anyways, on with the show, eh...
    As mentioned above, FLC8S has a lot of tuning options. So as opposed to trying to impress you more with vivd descriptions of their amazing sound, I'm going to discuss the various tuning options and which I prefer. Let's start with a run-down of the various tuning filters.
    Ultra Low Frequency
    1. Clear = Minimum
    2. Gray = Medium
    3. Red = Maximum
    Low Frequency
    1. Clear = Minimum
    2. Gray = Medium
    3. Black = Maximum
    Mid + High Frequency
    1. Blue = Medium Mid Frequency + Low High Frequency
    2. Gunmetal = Medium Mid Frequency + Medium High Frequency
    3. Gold = Maximum Mid Frequency + Medium High Frequency
    4. Green = Medium Mid Frequency + Maximum High Frequency
    Ok, now you've seen all the tuning choices that await you. Perhaps you can guess what some of the trends are. Did you guess that most people prefer the GRAY and RED ULF tuning plugs? Yup! Perhaps they also prefer the GRAY and BLACK LF tuning plugs? Right again! You also think most people like the GUNMETAL and GOLD MF + HF tuning nozzles? Man, you're good! You got them all right!!!
    I played around with the various tuning plugs and nozzles and rapidly came to the conclusion that I'm not a fan of using the clear tuning plugs at all. They gut the bass. Not a fan of the blue tuning nozzle. Guts the upper end. Green's not my favorite, either. It's ok, but it's got a bit too much upper end energy for me for general listening purposes. After nailing down which tuning plugs and filters I'd rather avoid, I started working with my preferred tuning accessories to hone in on my favorite combinations. 
    My hands-down favorite is RED-GRAY-GOLD Well-extended bass with good bass impact. Mid-bass is very well balanced with sub-bass. upper bass is reigned in. Very nice. Not boomy. Mids are tilted a bit towards the upper mids. The upper end conveys a good amount of detail without veering into harsh territory. I'd highly recommend using that as a starting point and then try substuting one of the tuning plugs at a time to hone in on your favorite. 
    Some of my other favorite tunings are:
    1. RED-GRAY-GUNMETAL. This is very similar to the RED-GRAY-GOLD combo up above but the upper mids are a bit more relaxed. A nice warm, relaxed listen.
    2. GRAY-GRAY-GUNMETAL. This is the default combination and works very well as a reference tuning.
    3. RED-BLACK-GOLD. Choose this when it's party time and let the bass kick!
    Beyond the basic tuning, FLC8S is able to convey a good sense of space and spacial cues. It's not the best I've heard, but it is above average for it's price and competitive with higher priced IEM. Of course some of this is source dependent, and I've found FLC8S scales well with increasingly better sources. I've tested it out with my iPhone 5s, Aune M2, Cayin N5, iBasso, Shanling M2 & M3, Soundaware Esther Analog, and most recently the Lotoo PAW Gold. While the FLC8S sound just fine out of my iPhone, add a decent amp to your audio chain or plug them into an entry level DAP and you notice the dynamics are a bit better and the soundstage increases. Move up to a mid-level DAP, and again the FLC8S doesnt at all feel like it's holding your audio chain back. Hell, I'm listening to them out of the PAW Gold I just got in for testing, and it sounds amazing! It's with PAW Gold that I can really hear FLC8S performing at its highest level, and the benefits of the new silver cable are most evident. So if you get the FLC8S, just know that it'll keep up with you as you upgrade your audio chain.
    I've skimmed some of the other reviews. While I consider the ability to alter the tuning a major strength of the FLC8S, I noticed that a couple people seemed to feel it was a gimmick. Obviously, I disagree. Let me be completely realistic about this. I don't expect anyone is going to be out on the bus and think to themselves, "Hey, I want to change filters on my FLC8S right now." That's pretty unrealistic. However, every once in awhile I do like to change the filters. Like I pointed out above, FLC8S can be a reference-tuned IEM if you configure it properly. So if you need that, it's there for you. Want to throw on some bass-laden hip-hop or electronic music and just give in and have some party time fun? Yup, you can do that, too. Feel like a v-shaped sound sig? FLC8S has you covered. you can even get a dark, warm sound signature if you throw on the BLUE tuning nozzle. Of course, you'll probably go right back to your favorite tuning afterwards. So what? At least you didn't have to go out and buy another IEM to get a taste of those other sound signatures. FLC8S has you covered, baby!


    By now, I certainly hope you're intrigued by these. I truly feel that FLC8S are an undiscovered gem in the IEM universe and hope they finally start to get the attention they deserve. Make no doubt, these are a phenomenal IEM with great sound in a nice, comfortable, small package. Add the ability to tune them to your liking, and they're a force to be reckoned with. And in my opinion, Forrest did a great job creating a highly-tunable IEM. Are they perfect? No. Are any IEM perfect? Of course not, and don't let anyone try to convince you otherwise!
    So what could be better? Well, I mentioned a few minor nitpicks along the way like microphonics, the overly tight cable cinch, and limited tip selection. Luckily the FLC8S have detachable cables, so if you end up falling in love with them you can always look around for a cable that fits your individual needs. There, that problem's solved. Tips? Well, who amongst us doesn't have way too many tips floating around? I mean honestly, I've got more tips than I know what to do with! So that's not really a big deal, either. The one thing that can't be changed is the very small tuning accessories. I know a lot of prospective FLC owners will be nervous about using them. Luckily you can purchase replacements, so just order a set of replacements when you order the FLC8S and you'll be set!
    To wrap, I'd like to congratulate Forrest at FLC for crafting a superb IEM that is competitive with IEM that cost significantly more. I look forward to your future creations with great anticipation!
      mgunin, elnero, Tony1110 and 14 others like this.
    1. View previous replies...
    2. canali
      Btw great review...kudos...enjoyed reading about Forest's background, too. Wish we'd get more bio stuff from the smaller new companies...adds both a bit of charm and respect for the skillsets they're bringing to the table.
      canali, Jan 29, 2016
    3. jinxy245
      I'm so intrigued by these...thanks for the review. You can obviously write a really (REALLY) long review, but you were concise and very readable... Thx!!
      jinxy245, Feb 17, 2016
    4. Arsalan
      Thanks for review.
      Which one would be better?
      Dudu 2002 or FLC8s
      Arsalan, Aug 7, 2016
  5. Hisoundfi
    Choose your own adventure... The FLC 8S triple driver hybrid in-ear monitor with tuning filters
    Written by Hisoundfi
    Published Mar 28, 2017
    Pros - Professional fit and sound, Filters designed to shape all frequency ranges (36 different tunings), Nice accessories package
    Cons - Cable is stiff with lots of spring and memory, Changing the low frequency filters is tedious
    At the time this review was written the FLC 8S was listed for sale on Amazon and Musicteck’s website. Here are links for more information and purchase.
    I’ve been around the headphone scene long enough to have my doubts about companies pushing their “new technology” products. I say this because often times it’s a gimmick to get you to buy something new. “Revolutionary sound damping technology” can be a company’s creative way of saying they put a layer of wool or paper over their drivers to dampen the high frequencies. Don’t be fooled by a lot of the mumbo jumbo. Do your homework and most importantly buy what you think sounds best, and at a price you’re comfortable paying.
    When it comes to tuning earphones manufacturers start with a driver and enclosure, then change the amount of air that flows on each side of the driver. That, or they add dampers to control how much of each frequency makes it to the listener’s ear. While I’ve seen many earphones that come with tuning filters I haven’t seen much out there that allows the owner to shape the sound from top to bottom.
    Most filters are nozzle replacements that control the upper mid-range and high frequencies. Although that’s an effective and fun product, often time owners come up short of what they consider the most ideal sound for their exact preferences. By the time something goes mainstream we’re often times already thinking about what we want next. This applies to the concept of sound shaping as well.
    When I was a young there was very popular literature amongst my childhood peers called “choose your own adventure” books. The decisions you made while reading them determined the pages you would read next. The result was a book whose story changed and depended on what we wanted to choose. The added element of choice made reading them a lot more fun.
    About a year ago the FLC brought to market a “choose your own adventure” earphone. Instead of one set of interchangeable nozzle filters, the 8S has three different ports to adjust sound. Many of my fellow Head-Fiers who heard them raved about the product. Although I didn’t have a chance to try them until recently, I trusted the impressions of those who did and kept them on my review radar. The main question that remained for me was just how effective the filter system was in terms of changing each frequency.
    When Musicteck contacted me to see if I was interested in reviewing the 8S I jumped on the chance. The main reasons were to see what the hype was all about, and also see if the filter system worked as advertised. If FLC was able to shape the entire spectrum of sound, the next big thing in in-ear monitors is already here. Let’s find out if FLC accomplished this and go over them with a comprehensive review.
    I was given a free review sample of the FLC 8S in exchange for my honest opinion and review. I am in no way affiliated with FLC. I’d like to personally thank Andrew for the opportunity, and allowing me to share my honest and unbiased opinion with the Head-Fi community.
    The FLC 8S comes in a light brown box with silver accents. Not a lot to say here…
    A magnetized tab flips open to reveal the earphones resting in a custom foam inlay. From that point various tabs cleverly open to reveal the accessories. The uniquely designed box leaves owners thinking they’re in for a real treat. If they can package them this clever, the earphones must be fancy too, right?
    Specifications and Accessories
    Driver unit: 8.6 mm dynamic drivers+ dual balanced armatures
    Rated Impedance: 11 Ohm
    Sensitivity: 107 dB/mW
    Frequency response: 20Hz- 20KHz
    Plug: 3.5mm gold-plated plug
    Cable: 1.30 mm TPU cable
    1X Pair of FLC 8S earphone
    1X Modular earphone cable with 0.75 mm two pin connection
    8X Pairs of silicon tips (S,M,L)
    1X Metal hard case
    1X Pair tweezers
    1X filter tuning set and metal carrying case (multiple tuning filters with extras)
    1X Airline adapter
    1X ¼ inch adapter
    Build and Design
    The 8S housings appear to be made of uniquely shaped high density plastic. The housings seem to be very durable and I don’t see there being any weak points. The shape is set up for an over the ear fit. A rubber filter can be seen on the inner and outer parts of the housings. The first thing I thought when looking at the filters is “wow, these are tiny!” Another filter can be seen screwed into the nozzle. Overall I’m happy with the shape. The FLC 8S comes in two colors, midnight teal and red.
    Holding them in my hand, the first thing I notice is that the cable is stiff, almost too stiff. There’s lots of spring and memory. I took a look at the owner’s manual and it states that the cable is specially designed for the FLC 8S, has quality innards and they encourage that owners don’t remove and replace the cable. Because of this I didn’t mess around too much with it. Although the cable has a considerable amount of spring and memory it’s not the worst I’ve seen and the included chin and neck slider helps snug things into place. The angled two pin connection looks like it will help with ergonomics. The 8S has a ninety degree angled plug with a 3.5mm jack. Strain reliefs seem reliable and strong. There is no microphone or remote, but the modular cable makes this a possible upgrade for owners looking to do so.
    Ergonomics, Fit & Isolation
    The FLC 8S provides a very good over the ear fit. Once you find the right tip, the earphones can be popped in, looped over the ear and snugged into place with the included chin/neck slider. I could wear the 8S for an extended period of time without needing to readjust the fit. The included tips provide a relatively shallow fit and are a softer silicone material with a wide bore. Tip rolling was relatively easy to do thanks to the fairly standard nozzle size. On a whole, isolation is average and depends on what filter you use. I could hear ambient noises, but they were eliminated once music was playing.

    Now to the good stuff…
    The 8S filter system works. Yes it works, but I don’t consider it a perfect system.
    There are three ports. The inner port of the housing shells tunes the earphones lowest “ultra low” frequencies (sub bass). The outer housing port controls bass tones above the lowest frequencies. There are metal pins that screw into the nozzles that control the mid-range and high frequencies. Although the system works pretty decently, I do wish the three filter tuning was split differently and into thirds (lows, mids, highs). Still, it’s not a big deal because the FLC accomplishes the same thing but in a unique and different way than I’d prefer.
    The filter system is stored in a blue metal canister that attaches to a key ring. Although I can see some people taking the filter system with them by attaching it to their keys, I don’t consider this filter system ultra portable, and definitely not something you can switch out on the go.
    To change the filters I strongly suggest you change them on a counter, under good lighting, take your time and be very careful. The biggest gripe I have about the FLC 8S is that the lower frequency filters that attach to the housings are TINY and tedious to change. You can easily lose (or break) these filters if you aren’t careful. Because of this, the 8S comes with one extra of each of the lower frequency filters (in a ziplock bag). Although the 8S comes with a pair of tweezers to help with the process of changing the filters, I didn’t find it very useful. I would suggest you keep a little extra slack on your fingernails and carefully use them to pry and place the filters how and where you want.
    The lower frequency filters are made of rubber and appear to have damping materials on the inner parts of them. The filters are pressed into the corresponding holes and are securely held in place with pressure placed upon the rubber tubes from the diameter of the holes of the housings. These filters control the amount of porting to the dynamic driver, altering the earphones’ bass response.
    The midrange and treble are adjusted by unscrewing and screwing various metal pins into the 8S housings. I really enjoyed using these filters. They were very easy to switch out. Moving forward, I hope FLC incorporates this threaded option to the other frequencies it will be an improvement.
    With all this said, the beauty of the FLC 8S is that it does exactly what it says it does. I can shape the sound to be ideal. After weeks of trial, error and comparisons I’ve found my favorite filter system. Let’s discuss this more in the sound portion of the review.
    Don't take just my word for it. Forrest, the man who invented these earphones has made a video describing the incredible technology these things have. Here it is:
    Source Matching
    The 8S comes in at 11 Ohms and 107dB of sensitivity. That is pretty sensitive and doesn’t require more than a phone or portable DAP in low gain. Although they will work with desktop gear, I didn’t get any noticeable benefit from added amplification. If you want to improve the sound of these earphones beyond the tuning filters, focus on using higher quality recordings and increased bit rate music files.
    The 8S sounded awesome with my LG V20 and iFi micro iDSD. Honestly, the 8S works with all of my portable sources. If something sounded like it could use something, it was a matter of changing filters to accomplish what I was looking for.
    Sound Review
    Because there are 36 different tuning options I can’t go over each one without writing a book about them. Instead I’ll share my experience with them and what I found to be my favorite filter combination.
    Putting into considerations the multiple tuning configurations, FLC has taken out some of the leg work by listing some recommended filter combos in the owner’s manual. They’ve also nailed it in terms of describing each of the filter combinations. I honestly couldn’t describe it any better than they have. You can try to come up with a better filter combination than what FLC recommends, but after trying just about every filter combination I came to the conclusion that FLC has identified and highlighted the best ones of the bunch.
    Switching the “ultra low” and “bass” filters is tedious. Here’s a tip, go with the recommended filter combos first. Once you’ve done this you will have a feel for what each filter offers, then be able to tweak it to your preference if you need to. If you don’t have the hands and coordination of a surgeon, you’ll be better off changing the lower frequency filters as little as possible. At this point I’m just glad I haven’t lost any yet.
    I got flustered changing the filters and putting the unused filters back in the carrying case, at which point I decided to find the combination I like best and haven’t looked back. The “balanced” combination is my favorite, and offers a very even tuning from top to bottom.
    The good news is that once you find your favorite filter combination, these are some of the best sounding hybrid in ear monitors I’ve heard. There is enough variance in the sound filters to say I’m confident just about everyone will come up with something they find ideal (or very, very close). If your preference changes a bit over time, there is a sound tweaking tool kit waiting for you.
    The FLC 8S covers every frequency from the lowest of lows to the highest of highs. Although the mid/high frequency filters aren’t ideal tools for tweaking each sound one by one, you can use various filter combinations in conjunction with them to make it work. Yes, FLC has given me the power to shape sound from top to bottom, and that’s awesome! To add to this, the separation of sounds is great. Detail is top of the line, and extension is great in both directions.
    Comparison to the LZ-A4 ($199 USD on many sites)
    The FLC 8S has a direct competitor and it’s the LZ-A4. The A4 came after the 8S and made some interesting tweaks. It’s a three way hybrid (just like the 8S) and comes with tuning filters that adjust the lower, middle and higher frequencies.
    Comparing the two, LZ has done some things that trumps the 8S. The housing shape promotes both and under and over the ear fit and the cable is much more manageable and easy to use. LZ has incorporated a MMCX connection as compared to the two pin connection of the 8S (you pick which one you like more). A big plus for the LZ-A4 is that the tuning system is much easier to use than the FLC 8S. I am more apt to changing the filters on the go. Build quality on both is about the same.
    With all that said you may be wondering why people would still consider the 8S. I personally feel that the 8S justifies its asking price over the A4 in a few ways including where it matters most, SOUND. The A4 sounds great, but the 8S gives me more control of the frequency response. The filters (although a PITA to use) are more precise, like precision tools used to perfect the sound to my liking. Simply put, when it comes to sound I can dial it in better with the 8S as compared to the A4. Also, the entire package of the 8S from materials and design to accessories is more professional and less generic than the A4. The A4 may be more fun and easy to use, but the 8S has superior fidelity.
    With the A4 I can adjust the bass three ways. With the 8S I can adjust it nine ways. For the most part the bass of the A4 lingers and decays slower than the 8S (with preferred filter combos). Compared to my ideal filter combination with the 8S, the A4 bass is a bit more sluggish in comparison. After my ears adjust to the 8S tuning, the sound is more natural and with more air between instruments and vocals. When my ears adjust to the A4 it seems to have more musicality and a more consumer friendly tuning. You won’t go wrong with either, but if maximizing fidelity is most important to you, I strongly suggest the 8S.
    The tuning filters of the 8S are not a gimmick, they’re the real deal and do exactly what they say they can. I can achieve just about any sound signature I want with them, and that’s awesome! At this time I can’t think of another product that gives the owner the ability to adjust and fine tune the sound at this level (at any price). The 8S has a professional fit and premium package of accessories. These will work as a reference monitor for professional musicians, as a earphone for audiophiles who want to maximize their music experience, and for casual music listeners who want to take their listening experience to the next level. They are a design (and price) that caters and appeals to several different markets.
    There are some things that could be more ideal. The bass tuning filters are tiny and it’s tedious to change them. The cable is stiff and has a lot of spring and memory. The good news is that once you’ve found the right filter combination and put them on, both of these things become a non-issue. The fact that I can take the 8S and make the earphone sound exactly how I want it to, I can overlook these two things. At the end of the day it’s all about sound for me. The 8S not only delivers high quality sound, it does it with an ideal tuning for my preference.
    When rating a product I have to take all criteria into account (including price). The FLC 8S gets four and half stars for build and design, four and a half stars for ergonomics, three and a half stars for functionality (springy cable and changing filters is a pain), and FIVE BIG STARS for sound. They are the current king when it comes to shaping sound.
    Thanks for reading and happy listening!
      mgunin, Katie88, tarhana and 10 others like this.
    1. View previous replies...
    2. LS13
      Great Review. Didn't notice them listed in your profile but have you had a chance to compare these, to the iBasso IT03?
      LS13, Mar 29, 2017
    3. Hisoundfi
      I haven't heard the iBasso IT03. Sorry buddy.
      Hisoundfi, Mar 29, 2017
    4. originalsnuffy
      There was a fair question about whether these can be considered as near TOTL. My take; with certain tunings these sure sound like TOTL units.

      I feel they are more comfortable and easier to fit than the IT03. Your mileage is sure to vary.
      originalsnuffy, Mar 29, 2017
  6. twister6
    Custom Tune the Sound, just the way YOU like it! FLC 8S Custom IEM Review
    Written by twister6
    Published Jun 13, 2016
    Pros - Resolving high def sound, pick from 36 filter combinations, premium replaceable cable, improved comfort w/custom fit design, unique storage case.
    Cons - small filter pieces, not a common 2-pin cable connector (UE style).

    This is a review of Custom IEM version of FLC8S 3-way hybrid IEM (will be referred in my review as FLC8C). The original FLC Technology FLC8S monitors are officially distributed by http://www.lendmeurears.com/flc-technology/, while the manufacturer website and FLC8C product page are still under development. I was told that expected price should be around 900-950 SGD, with faceplate options of carbon fiber (62 SGD), wood/metal/glitter/print (103 SGP), and steampunk (145 SGD). The review unit I received is a demo of a Custom FLC8 where the nozzle was modified to fit a regular eartip and the shell was modified for universal fit - set to me by LMUE in exchange for my honest opinion.
    6/14 update: Official FLC8S Custom LMUE page is up: http://www.lendmeurears.com/flc8s-custom/ and the price was set at $674.  The page includes pictures of 19 custom housing colors and 14 custom faceplate options.

    Often I’m being asked to recommend IEMs tuned for a specific sound signature or suited for a specific genre of music.  It’s not always the easy question to answer because the perception of a sound varies between people, and everybody has their own subjective opinion about it.  Even headphones tuned for a particular signature still have a degree of sound variation from the expected baseline.  And once we settle on a pair of headphones that we like, many still have a desire to continue with fine tuning by switching to different eartips which can change the amount of bass or switching to a premium cable which can add more sparkle to the sound.  Depending on a model, some IEMs even offer replaceable nozzle filters for a more noticeable sound adjustment, but nothing too drastic.
    One headphone manufacturer decided to take the idea of sound tuning a step further, and actually leapfrogged to a whole new level with a patented filter system like nothing I have seen before.  Even so FLC Technologies was started by Forrest Wei not too long ago (in 2011), he has many years of experience working for Ultimate Ears, Jabra, MWM Acoustics, and Harman.  With all this experience under his belt and fueled by a passion for design and innovation, Forrest made a serious attempt to reinvent the wheel of IEM sound tuning by using multiple filters in his debut release of 3-way hybrid FLC8, later replaced by FLC8S with improved build quality and updated cable.  Now, with a support of Teo and his Lend Me UR Ears, they are taking it to yet another level with soon to be available Custom model which I had a chance to test and would like to share with you about.
    Unboxing and Accessories.
    While the original FLC8S featured a unique jewelry box packaging (similar to PAW Gold box), FLC8 Custom (FLC8C) stepped it up with VIP Aluminum mini-briefcase box with a stamped FLC Technology logo on the top cover.  Actually, it comes in a cardboard box with a see-through film window on the top, but once you lift that top open you will see a legitimate high quality aluminum mini-briefcase with a latch.  The only thing missing was a handle which would have been cool.
    With a storage briefcase open, you will find removable egg crate foam lining in the top cover and a layer of foam lining with cutout partitioning on the bottom.  When it comes to the included accessories, the owners of the original FLC8S won’t find any surprises.  You get their familiar metal round storage container which has a top part with a thread to keep it securely closed, and unfortunately still lacking a lining to protect its content from banging inside during the transport.
    You also get 1/4" adapter and an airplane plug.  I consider both to be fillers – but hey, maybe some will find it useful.  A basic cleaning tool was included (actually there was two), one to clean bores of the nozzle and the other one probably to help with removal of nozzle filter.  I also received a set of eartips because my review pair of FLC8C was designed with universal nozzle to fit eartips.
    The package wouldn’t be complete without plastic fine point tweezers to assist in handling of small filter parts, and the blue bullet keychain designed to store various filter pieces fitted inside of its rubber holder.  Very generously, Lend Me UR Ears also included a 2nd set of filters in a small plastic bag – it’s easy to lose them during removal/install, thus an extra set was very welcome, and it could be purchased separately as well.  The included manual was in Chinese, but I was able to correlate filter designation by comparing to FLC8S English manual.  ULF and LF filters are the same, and instead of a removable nozzle (MF/HF) filters, now you have double plug with a few different colors I had to guess.  When FLC8C is ready for international shipment, a translated English manual will be included.
    flc_flc8C-01_zpsliyme2al.jpg   flc_flc8C-02_zpscq95bwti.jpg
    flc_flc8C-03_zpspx0sgcn3.jpg   flc_flc8C-04_zpsltmpktni.jpg
    flc_flc8C-05_zpsw9fekfcj.jpg   flc_flc8C-06_zps5s7m6int.jpg
    flc_flc8C-07_zpsnjhvi7ru.jpg   flc_flc8C-08_zpsazqooxrq.jpg
    flc_flc8C-09_zpsbmdxwsbh.jpg   flc_flc8C-10_zpspnr7frpj.jpg
    I haven’t seen the cable from the original FLC8, but the fact it was updated in FLC8S tells me it had some issues.  Also during my brief testing of FLC8S, I wasn’t too crazy about its OFC cable either due to a rather springy wire and some microphonics.  Another annoying part of it, it uses a 2pin connector which is not universal but rather 0.75mm type found in legendary UE TF10 (hint, hint – Forrest connection to UE).  It’s definitely not the end of the world since you can still find replacement aftermarket cables with this connector, and any custom cable maker can utilize it as well.  But I wasn’t able to take advantage of my collection of aftermarket universal 2pin cables because they don’t accommodate 0.75mm spec.  As a matter of fact, you have to be very careful not to jam other cables by mistake.  Also, even so I had no issues with it, the connection of this UE-style socket is not as tight and secure as a common universal 2pin connector.
    But there is a “silver” lining to this cable situation – FLC8C comes with a single crystal silver upgrade cable, an included $107 bonus which can be purchased separately as FLC8S accessory from Lend Me UR Ears.  I actually like this cable a lot better over the original one included with FLC8S.  It still has some memory effect, but not as springy, has a heat shrink tube for y-splitter, another sliding tube piece which functions as a chin slider, and a pre-shaped springy sleeve for over ear fit without annoying memory wires.  2pin connectors were angled and had red/black ID dots, and on the other side of the cable you have a right angled 3.5mm TRS headphone plug with a decent strain relief.  All 4 wires go to the connector, so would have been great to terminate it with a straight 2.5mm TRRS balanced plug and add 3.5mm TRS angled adapter – maybe something for FLC and Lend Me UR Ears to consider in a future.
    Now, the million dollar question:  is there a sound benefit when using “single crystal” silver cable over the stock OFC cable?  Being quite familiar with effects of different wire material which I have tested across many IEMs/CIEMs and various cables from my review collection, I had some expectations when switching between FLC8S stock and FLC8C upgrade cables, but arrived to a different conclusion.  While testing with all gray filters, what I consider to be a baseline sound sig, surprisingly I found this silver wire cable to improve low end resolution and articulation without affecting too much mids or highs.  It improves sub-bass texture and slightly elevates its quantity which in a relatively comparison was a bit rolled off with a stock OFC cable.  This is not a typical sound change I hear with my other thicker wire pure silver cables that usually brighten the sound of other IEMs I tested, but regardless of that – I liked the effect of this cable on FLC8C.
    Even without a sound improvement, I still like the new cable design and consider it to be a step up from the original FLC8S cable.  The improvement in bass performance, as I hear it, is just a bonus.  But I was still left wanting to try it with other silver or silver plated cables to hear the difference.  I hope down the road FLC will consider switching to a more common 0.78mm 2pin connector design, or at least offer it as an option when choosing Custom configuration of this IEM.
    flc_flc8C-11_zpsebopmot5.jpg   flc_flc8C-12_zpspwehvkoz.jpg
    flc_flc8C-13_zpszo55fbp7.jpg   flc_flc8C-14_zpsgherxd3d.jpg
    I’m still amazed how FLC was able to fit a dynamic driver and a pair of BA drivers all inside of their original slim lightweight FLC8S shell.  Though I have seen the diagram of the 8S design, I would have loved a glimpse inside through a transparent shell to see it "in person".  Also, I was a bit on the fence about the fit due to combination of a small shell with a springy cable.  This is purely a subjective opinion and probably has to do with my ear anatomy, but on a few occasions the earpiece popped out of my ear, and a thought cross my mind wishing for the shell to be bigger.  Custom version of FLC8 turned out to be the answer to this prayer!  Actually intended for audio trade shows, FLC and Lend Me UR Ears made a few samples where the shell was modified to have a universal shape to fit any ear and the nozzle was replaced with a universal 2-bore design which accepts common eartips.
    Obviously, the official Custom version will be designed from your ear impression mold which you need to get from your local audiologist, and the final shell design should fit your ear like a glove.  But even with Universal version of this Custom FLC8C, I was able to get an excellent fit with a great isolation.  Once it becomes available, you will be able to customize it, including different faceplate designs such as carbon fiber, wood, metal, glitter, custom print, and even steampunk.  My review unit arrived in a semi-transparent yellow color shell, and I was grateful for being able to take a glimpse inside to see the arrangement of the drivers, and how the sound tubes and filters interact with each other.  As a result of these Universal-Custom modifications, my review unit ended up looking a bit Frankenstein-ish, but I'm sure the official Custom shell will have a more premium look.
    The biggest selling point of this design, at least for me personally, was the larger size shells and a better quality cable which yielded a perfect fit and improved comfort to the point where I forgot I even had them in my ears.  Just don't expect to fall asleep with your head down on the pillow while wearing FLC8C since they are not exactly flush and do stick out a bit.
    flc_flc8C-16_zpsbgjmaq7n.jpg   flc_flc8C-17_zps2jek3xpk.jpg
    flc_flc8C-18_zpscvfadwi0.jpg   flc_flc8C-19_zpsow6zheml.jpg
    flc_flc8C-20_zpsg1cyxccf.jpg   flc_flc8C-21_zpsqvqbdvjq.jpg
    The fit.
    Sound Filters.
    I'm sure many associate IEM filters with some sort of a replaceable nozzle filter and a predictable selection of three pieces with a default sound, reduced bass sound, and enhanced bass sound.  FLC decided to approach the filtering method in a completely different way.  They split their filters into 3 groups: ULF (ultra low frequency, associated with sub-bass), LF (low frequency, associated with mid-bass), and MF/HF (mid and high frequencies associated with midrange and treble).  Keep in mind, this is a hybrid design, thus ULF and LF will be focused on fine tuning the sound of Dynamic Driver, and MF/HF will be focused on fine tuning the sound of Dual BA drivers.
    This filtering system is nearly the same as found in FLC8S, with the only exception of a nozzle filter.  With 8S being a more traditional universal design, you unscrew and replace the nozzle part which controls a combined bore opening.  Custom FLC8C has a 2-bore nozzle design with a dual rubber-plug filter to control MF/HF.  Having the advantage of a clear shell, I can trace the path from a Dual BA going to one of the bores where the corresponding side of the dual plug has an actual filter while the Dynamic Driver (DD) goes to another bore and that side of a dual plug filter only varies in the opening width.
    The actual filtering of DD is done through 2 vents in the shell using the corresponding ULF and LF filter plugs.  The low frequency (LF) replaceable rubber plug goes into the vent located right across the DD.  The sub-bass frequency replaceable plastic push pin (ULF) goes into the separate vent with a tube connected to the output of DD driver.
    Each earpiece has 3 filters, one going into the nozzle and the other two going into the faceplate of the shell.  Each filter is color coded and corresponds to the following:
    ULF: clear - less ULF, gray - medium ULF, red - most ULF
    LF: clear - less LF, gray - medium LF, black - most LF
    MF/HF: clear - lower HF, gray - medium MF and medium HF, gold - most MF and medium HF, green - medium MF and most HF.
    If you do the math, you'll end up with 36 different sound combinations!!!  I'm not aware of any other IEM that can pull off the same.
    Sound Analysis.
    With so many unique sound combinations, how would you even describe the sound?  Based on filter description where gray is considered to be a happy "medium", I started with that setting as a baseline sound of FLC8C.  With all 3 filters selected as gray, I hear a very resolving, reference quality, expanded sound with a balanced signature, excellent retrieval of details, and an impressive transparency.  FLC8C has an excellent extension of the low end and high end (deep low end extension down to sub-bass, very textured, very articulate), punchy mid-bass, nicely balanced mids with just a perfect amount of body and excellent retrieval of details, sometime even down to a micro-detail level, and a high definition crisp airy treble.
    Soundstage is definitely above the average, though I do hear a bit more width then depth.  Layering and separation of instruments and vocals is very good, with a decent imaging that has a very convincing placement of instruments and vocals which actually improves as you switch to brighter high frequency filters.
    Now, starting with this all-gray baseline, I will go into a brief description of each filter variation and its effect on the sound.
    *** MF/HF variation
    gray - gray - clear: treble and upper mids are a little rolled off, while low end and lower mids stay the same, sound becomes a little smoother and warmer.
    gray - gray - gold: lower mids become a little bit thicker but not muddy, and as a result of this I hear treble a bit rolled off.
    gray - gray - green: treble gets boosted and becomes a bit grainy, but you do hear an improvement in airiness.
    *** LF variation
    gray - clear - gray: noticeable reduction in mid-bass where it becomes more neutral and flat.  It also thins out lower mids a bit, making sound more reference quality.
    gray - black - gray: adds more mid-bass hump, the same speed, just a little bit of quantity boost, but I do hear more body in lower mids which now sound a lot thicker, making overall sound a bit less transparent.
    *** ULF variation
    clear - gray - gray: i do hear sub-bass slightly more rolled off, but it's a rather subtle change, sub-bass is still extended but has a little less quantity.
    red - gray - gray: beefs up sub-bass without too much exaggeration which also improves the impact of the mid-bass. While LF boost affects lower mids, ULF boost affects/improves the whole sub-/mid-bass in a very positive and controlled way.
    *** favorite combo ***
    red - gray - gold: my favorite low end setting with a very articulate and well controlled bass and a smooth yet still detailed top end.
    red - gray - gray: the same as above, but with a more revealing and airy top end.
    flc_flc8C-28_zpsc488up6v.jpg   flc_flc8C-23_zps3oscfray.jpg
    flc_flc8C-24_zpsikffyzso.jpg   flc_flc8C-25_zpsb5p2ewlh.jpg
    flc_flc8C-26_zpsua1z20zv.jpg   flc_flc8C-27_zpswk2mmg9w.jpg
    Comparison to other headphones.
    This comparison was done using PAW Gold as a source, and FLC8C in its default filter config (except for 8S vs 8C comparison).
    FLC8S vs FLC8C – even so we are dealing with the same 3-way hybrid design and nearly the same filtering system, the shell design and the nozzle filter difference should account for some changes.  I used my favorite red-gray-gold filter setting on both for a comparison.  The first difference I hear is 8C soundstage being a little wider, while 8S has a little more depth.  The bass and the treble between these two sounds nearly identical, but I hear the difference in mids where 8C has more energy and a little better retrieval of details while 8S mids sound a little dryer and more withdrawn.
    FLC8C vs DN2kJ - DN has a similar soundstage expansion, not as deep sub-bass extension, more neutral bass in comparison, leaner lower mids, brighter upper mids, detail retrieval is similar (though DN is more analytical), DN has slightly better treble extension with more airiness.  Overall FLC8C is smoother with fuller body vs DN2kJ being leaner and more vivid.
    FLC8C vs Primacy - similar resolution but Primacy by default has a more lifted low end with a heftier sub-bass and a stronger mid-bass, a little more body in lower mids, similar upper mids, and more rolled off treble.  Very similar soundstage, though FLC is a little bit wider.
    FLC8C vs A83 - FLC soundstage is a little wider.  Mids and treble are very similar but the big difference is that A83 has more impact in the low end with deeper sub-bass and more mid-bass punch.  In this comparison FLC is more balanced and has a little better resolution.
    Regardless of Universal or Custom design, FLC8x is one very impressive pair of 3-way hybrid IEMs with an excellent resolution, great sound extension and soundstage expansion, and a very flexible sound tuning.  Its triple-filter sound customization is what sets it apart from any other tunable monitor I have ever tested.  You almost feel like a sound designer, going through different filter combinations, adjusting the sub-bass, mid-bass, mids, and treble to tailor it to your exact liking.  It's true that filtering pieces are very small to handle, but typically you shouldn't be going back'n'forth with constant adjustments, though it's tempting.
    The biggest question in here is if Custom FLC8C worth nearly the double price of Universal FLC8S?  The word "double" has quite a weight to it, until you stop and think about the actual price of the universal version and realize that if you take into account a premium cable and a premium aluminum storage case, you are only paying about extra $200 for an improved Custom shell design with a superior fit and isolation.  I have a feeling many diehard fans of FLC8S will probably justify this price difference to turn this one of a kind 3-way hybrid IEM into one of a kind Custom fit earpiece.  And for those who have been eyeballing FLC8x design, the FLC8S still has one great value.
      Raketen, Brooko, Koolpep and 9 others like this.
    1. View previous replies...
    2. twister6
      @Wyd4 : keep in mind, my review CIEM unit was a demo modified to be universal so I can use with eartips.  For the Custom version of FLC8S you need to send your ear impression and you will have a custom made shell with all the corresponding "commitments" :wink:  Maybe you can ask them to make a special order with universal custom shell.  If enough people request, I'm sure it will get FLC/LMUE attention to add it to their customization list.
      twister6, Jun 15, 2016
    3. Wyd4
      Oh apologies. For me the biggest worry with ciem is the what if the sound isnt quite for me. This monitor eliminates that to a degree.
      Wyd4, Jun 15, 2016
    4. Arsalan
      Thanks for review. Which one is a better choice?
      Dunu 2002 or FLC8s?
      Arsalan, Aug 7, 2016
  7. d marc0
    The hybrid in-ear monitor with tuning capabilities of up to 36 sound variations!
    Written by d marc0
    Published Mar 4, 2016
    Pros - Tunable with 36 sound variations, comfortable fit, good sound performance
    Cons - short cable, tiny-easy to lose parts
    Hybrid In-Ear Monitors (IEM) now have their own fanbase following the emergence of the first universal high-end one in 2011. Earphone manufacturers recognised this and have since produced their versions of the hybrid configuration: Dynamic Drivers for bass + Balanced Armature Drivers for midrange and treble. I’m proud to say that I am a bonafide hybrid IEM fan. The benefits of having both dynamic and balanced armature drivers in one IEM are unique, almost impossible to replicate with a single driver design. Dynamic drivers offer a natural bass timbre; add that to the superior midrange-to-treble clarity of balanced armature drivers, the end result can be fantastic! That’s If they tuned it right… easier said that done.

    Aside from the hybrid driver configuration, adjustable sound or tuning has become a common feature amongst in-ear monitors. We’ve seen interchangeable tuning filters that can alter the upper midrange and high frequency responses. Other models have bass rings that will cover bass vents, therefore increasing the bass impact and sub-bass extension. In the case of FLC Technology’s hybrid IEM, three tuning methods were utilised, allowing various combinations to shape a sound signature that’ll match your preference. So here, we have the FLC 8S – the hybrid in-ear monitor with tuning capabilities of up to 36 sound variations.

    RETAIL PRICE:           US$ 335
    DRIVER SPEC:           8.6 mm dynamic + dual balanced armature drivers
    IMPEDANCE:              11 Ohm
    SENSITIVITY:              93 dB/mW
    FREQ RESPONSE:    20Hz – 20KHz
    TERMINATIONS:        2-pin, 3.5 mm gold plated L-plug
    INCLUDED CABLE:   1.3 M TPU cable, 1.3 M OFC copper cable
    WHERE TO FIND:      lendmeurears.com

    Disclaimer: This review unit was provided as a loaner. Special thanks to @DJScope for facilitating the tour.


    FLC Technology did a decent job on the FLC 8S’ accessories. It shows that lot of thought came into play before finalising the retail packaging. However, I do think that a few more variations of ear tips and a shirt clip to assist in minimising cable noise (microphonics) could add more value to the overall package. Other than that, all the accessories that made the retail packaging are there to ensure good user experience.

    1. 8 pairs of silicon tips (S,M,L)
    2. 1 metal case
    3. 1 pair tweezers
    4. Low frequency tuning plug: nine (three groups, one group of three)
    5. ultra-low tuning plug: nine (three groups, one group of three)
    6. Tuning catheter: eight (four groups)


    iPod Touch 5th Gen > OPPO HA-2 DAC/AMP
    16/44 FLAC and ALAC
    T-PEOS hybrid silicon ear tips were used

    Dr. Chesky’s Ultimate Headphone Demonstration Disc
    Booker T. Jones – Representing Memphis
    Seductive Souls – How It Feels
    Pantera – Domination
    Daft Punk – Giorgio By Moroder
    Sia – Chandelier
    Jewel – Somewhere Over The Rainbow

    I really like the design and build of the FLC 8S. At a glance, it doesn’t look premium, but upon closer inspection, the plastic housings have a nice, smooth finish with no noticeable gaps. What’s obvious are the unique tuning ports, where the tuning plugs reside and the blue coloured theme from the housing, all the way to the tip of the cable. There are two different types of cables included, a black stock TPU cable, and the OFC copper cable which has the blue colour scheme. The black stock cable may look plain but it’s supple and lightweight. The lack of stiff ear guides make them the cable of choice for those who wear glasses. The aesthetically more pleasing OFC copper cable has a more sturdy build but it’s slightly stiff and retains some memory (shape). The blue cable is quite microphonic (cable noise) when rubbed onto clothes but easily minimised by attaching a shirt clip. Cable length can also be a concern because they seem a bit too short by today’s standard. The shape of the housing may not look the part but they conform to the shape of my ear. Inserting the IEM is very easy, and they sit securely like conventional ear plugs. I also find them very comfortable even after a few hours of listening sessions. Please note that your mileage may vary because we all have different ear shapes and sizes. I have small to average-sized ears so these IEMs will surely fit the majority.


    The tuning feature on the FLC 8S utilises three different adjustments, which sets this IEM apart from its hybrid counterparts. Four sets of tuning catheters can be interchanged and attached on to the nozzles; these are responsible for tuning the midrange and treble. To adjust the bass quantity, three sets of low frequency plugs are available for the front tuning ports. Last but not the least, three sets of ultra-low frequency plugs can be used to adjust the sub-bass extension. Mix and match… you’ll find 36 various combinations with noticeable difference in sound signature. At the end of the day, I believe  most users will stick with one or two combinations to match their preferred sound signature. My personal favourite is the recommended default combination: Gray Ultra Low Frequency (ULF) plug + Gray Low Frequency (LF) plug + Gunmetal (MF/HF) Nozzle catheter/filter. Please take note that the tuning plugs are very tiny and can easily be lost or misplaced. Changing the sound signature is a fiddly process and requires a proper setting to avoid losing parts. A pair of tweezers is included as a tool for installing the tuning plugs; please do not attempt to use the said tool for facial grooming *wink*.





    For the purpose of this review, I will be using the recommended default combination. This can serve as a reference for FLC 8S users; and by using the description of the tuning accessories above, one can estimate the effect of interchanging specific tuning plugs or nozzle filters. The sound presentation for the default combination is the most “balanced” when compared to the other combos. The Gray ULF and LF plugs’ effect is a slight accentuation in bass. The Gunmetal MF/HF catheter or nozzle filters effect on tuning is a neutral midrange with a smooth upper midrange; while the treble has a slight emphasis that projects more energy and extension.

    Most people seek a great bass response before anything else in the frequency spectrum. The same holds true for Hybrid IEM fans, the bass performance holds a massive influence on the buyer’s decision. Fortunately, the FLC 8S holds its own when it comes to bass control, texture, and layering. The test track used for this section was Giorgio By Moroder by Daft Punk. The details come through clearly with every bass guitar line and drum beat. Sub bass rumble is sufficiently felt. Timbre is quite organic and natural sounding, so differentiating various instruments is not a hard task with this IEM. The transition from bass to midrange is seamless, another testimony on the FLC 8S’ competence in keeping the midrange clear of bass bleed. While not the best in the market, the FLC 8S is competitive enough in its price range. Since this is a review, I’m going to nit pick and determine key areas for improvement. The bass decay times seem a tad bit slower than other high end IEMs. Bass tightness could also be improved to uplift its sense of urgency. Really minor nit picks but these shortcomings are noticeable when listening to fast bass lines or drum blasts. Pantera’s Domination from their debut album is an excellent track to demonstrate bass speed or decay times.


    Midrange is akin to the meat in a burger. It’s the main focus of the entire experience and the FLC 8S is as tasty as good burgers can get. Instruments and vocals sound naturally life-like. What impresses me is its ability to smoothen the upper midrange to relieve poorly mixed tracks of potential harshness. Sia’s all-time famous Chandelier is a track I use to test upper midrange control. Too much boost in this area and it’ll sound harsh, edgy and fatiguing. The FLC 8S manages to keep a more pleasing presentation, devoid of potential harshness. On the other hand, clean sounding tracks with piano or female vocals as a centrepiece might leave you wanting for more presence. Jewel’s rendition of the classic – Somewhere Over The Rainbow, presents an intimate vocal performance but clarity and definition seem to take a back seat when listening through the FLC 8S. Not quite noticeable but something to take note of if you’re a critical listener. Overall midrange balance is good and quite enjoyable for most modern music.


    I prefer the treble response to have ample energy, airiness and extension. Well, I’m happy to report that the FLC 8S passes with flying colours although with a caveat. There’s a slight over-emphasis in the treble response making the presentation a bit brighter than intended. Scratchiness and sibilance can be an issue at high listening volumes or brightly mixed recordings. Take Daft Punk’s Random Access Memories as an example. The entire album was intricately mixed and mastered that sibilance is non-existent even on the FLC 8S. Put in some early 90’s rock tracks and you’ll immediately hear the exaggerated SSS’s and cymbal crashes. As long as you’re particular with song selection and stick with quality recordings, the FLC 8S will continue to impress.

    Overall sound presentation from the FLC 8S is effortlessly grand in scale; more on the width of the soundstage rather than depth. Spacing between instruments or musical cues is above average, better than most IEMs in this price range that I’ve tried. Imaging could’ve been better if there was more depth but at least it’s good enough to maintain a cohesive presentation. The recommended default configuration has a nice, balanced sound signature. The low end frequency response is slightly on the warmer side of neutral. The mild accentuation in the treble region complements the low end warmth and helps maintain the overall balance. Listening to Seductive Souls – How It Feels, was quite a euphonic experience.


    The FLC 8S is a well featured high end hybrid IEM, thanks to its tuning capability. I don’t expect anyone with the FLC 8S to be changing combinations regularly, but it’s a good option to have when you feel the need. I would recommend the FLC 8S to those who are planning to upgrade from a beginner’s setup but unsure of their sound preference. Having the option to customise the sound to your liking is the safest way to avoid regrets in portable audio purchases. It is also a great solution for people who have hearing loss or sensitivity in specific areas of the frequency response. The FLC 8S is flexible enough to attenuate or accentuate certain frequencies that can help improve the user's listening experience. So it is important to try all the tuning combinations to find the sound variation that's perfect for you. I surely hope that FLC Technology will continue to innovate and produce wonderful products. They are already on the right track with the FLC 8S and a few more minor tweaks to the sound will move this product forward to top-of-the-line status.

    NOTE: The ratings meter above is inaccurate. It should be:


      Ritvik, Brooko, djvkool and 7 others like this.
    1. View previous replies...
    2. Rollk2
      Thanks, I'd like a comparison with the Savant :)
      Rollk2, Mar 8, 2016
    3. d marc0
      @Rollk2  You're welcome. It's quite hard to do a decent comparison because of the type of drivers and the various tuning. In general, the Grey ULF + Grey LF + Gold mid-hi is the closest in terms of signature. Bass on the Savant is tighter and nimble, while FLC has more depth and sub bass extension. Mids is quite similar between the two but the Savant has more laid back lower mids. Treble is where there's quite a difference. Savant is smoother while FLC8 has more energy and extension. Overall control is more refined on the Savant, the FLC8 can get a bit aggressive on some tracks. Hope that helps.
      d marc0, Mar 13, 2016
    4. Arsalan
      Thanks, which one would you buy? DUNU 2002 or FLC8s
      Arsalan, Aug 8, 2016
  8. H20Fidelity
    Great concept, great Idea
    Written by H20Fidelity
    Published Apr 27, 2016
    Pros - Adjustable sound signatures, great packaging,
    Cons - Caused some fit issues, cable lacks appeal, filters easy to lose
    FLC Technology were a company I'd never heard of until they surfaced on Head-fi late last year. They’re a Chinese based company with some very interesting ideas in regards to customizing your portable audio experience. Hybrid in-ear monitors have always been popular among the Head-fi crowd, with the use of a dynamic driver and balanced armature used in unity you can produce some excellent performance, it seems everyone including Sony are giving it a go. Where FLC Technology push the game further is adding a complete filter adjustable hybrid so you can cater the sound to 36 different approaches! 
    1. Sensitivity 107 dB/mW  @ 1000Hz
    2. Frequency Response 20Hz - 20Hz
    3. Drivers x1 8.6mm Dynamic + x2 Balanced Armature
    4. Impedance 11ohm
    5. Cable length 1.2m (detachable UE two pin configuration)
    1. $349 USD (found at lendmeurears.com and other selected vendors)
    Much thought went into the packaging the entire presentation arrives in a heavily built cardboard box with inserts that flick outwards and a design speech in itself, its not the kind of thing you would throw away after removing the earphones. Its built to last as a storage container for your accessories, filters and looks great in person. It is quite heavy though so one must take this into consideration.
    When I first laid eyes on FLC8 I would have believed the housings are actually metal or some form of durable aluminum, after some investigating it appears the housings are made of plastic, but like I said you'd never know unless you were told. This goes for the appearance and the feel of the housing. You can get them in two different colours (blue or red) and personally I think both look great with a little bias towards the red in colour.
    The cables are detectable as are the front filters which all appear to have decent threading and connections. There is however a short guide to take care when removing the cables as they're not 100% fool proof and can be damaged if care is not taken. I'll also add one should only remove the cables when absolutely required. While they're indeed detachable they're not 'indestructible'.
    I will say the cable is a little under the weather, it looks nice in photos but is a little stiff and doesn't feel all that premium to the touch, it has that wirey feeling that retains spring and may seem a little springy for those on the go in the outside world. The beauty of FLC8 is however it can use any third party UE two pin cable for those who want to upgrade, sound, aesthetics alike.
    Fit / Isolation:
    Unfortunately for me getting a fit with FLC8 was a little underwhelming, particularly the left side liked to pop out of my ear often, I was able to keep them secure by lifting my ear before inserting the tip however over time it would wiggle its way out and I found myself pushing the left earpiece back in. It was ok sitting down or lying in bed but on the go they gave me some issues no matter which way I adjusted the ear guide or tips used. I think maybe because the housing is unable to pivot.
    I will say the majority of owners (and there are many) have not had the same issues so it appears the fit issue would be isolated to a selected few who just don't fit the mold correctly. I had read one other thread on Head-fi where a member had the same issue. Isolation was also affected because of the fit issue but I'll say once sealed isolation was more than satisfactory but not an entirely strong point for my experience, especially outdoors.
    Included in the package is:
    1. x12 Silicon tips ( Small / Medium / Large)
    1. x1 Round metal case (very strong / durable)
    2. x9 Low frequency tuning plugs
    3. x9 Ultra Low frequency tuning plugs
    4. x8 Tuning nozzles
    5. x1 Pair of tweezers (for using installing the filters)
    6. x1 Filter storage case
    7. Airline adapter
    8. 6.3 to 3.5mm Jack Adapter
    9. Tuning guide
    10. Ear wax cleaning tool
    Filter System:
    The most inspiring part of FLC8 is the tunable filter system allowing up to 36 different sound signatures. By changing the nozzle and two small filters located on the housing you're able to alter the sound signature closer to something you prefer. You can adjust the ultra low frequency, low frequency and mid-range which is a separate filter that attaches to the housing nozzle.
    I will show some illustrated pictures from the supplied tuning guide:
    Because there are so many customization's available one would be mad to go through each one and write about them (absolutely mad I tell you). So what I have done is adjust FLC8 to what I feel is inline with my preferences which are bright/analytical. By doing this I'm able to mold FLC8 into something close as possible to my desired sound signature and write a sound description.
    The configuration I went for is:
    1. Red: Ultra Low Frequency
    2. Grey: Low Frequency
    3. Green: Mid-range Frequency
    Files used:
    1. FLAC 16/44 (all files)
    Sources used:

    1. iBasso DX80
    2. Cayin N5
    3. iBasso DX90
    With the red filters installed one of the best tracks to test sub-bass is Michel Jonasz – Le Temps Passe. Extension is good, the texture is great and there's a nice presence of clarity in the low-end. I won't say its the the most extended I've heard but most certainly a nice low -end. It has the correct speed and punch but still to my ears doesn't push out the most quantity. But even then its more than present and shows enough quality bass for its price range to impress the masses.
    With the green filters attached to the nozzles I was able to make FLC8 sound quite vibrant and on the brighter side, it makes a good experience for those who like a nice amount of clarity and detail in their presentation. I would even lean to say if your seal isn't correctly done you may even find them a little too lean. Detail levels are well present however I do wonder if something like Fidue A83 can push out a little more for the price between them.
    Refinement is nice, there's a nice tonality which again shimmers through the mid-range giving a quality timbre, areas like the upper mid-range have a nice push at times with vocals. All in all the quality of FLC8 is quite nice and I understand why people rave about them. There's hardly any siblance to be found and the earphone presents itself well.
    For testing treble and an IEMs ability to remain stable its always good to throw some modern recorded EDM tracks or electronic music, its these tracks that will test an the IEMs extension, refinement and strength at not showing any peaks or sibilance in the highs. FLC8 pulled this off nicely, even with the brighter green mid-range filters installed. It doesn't have the end to all in extension but does a clean job and showing itself.
    If I had to fault the treble it could sound a little metallic or one noted at times, Kind of ticking away in the background and allowing the mid-range to come through over the top. But again, I must stress this is just with my filter set up!
    Strong point, not the end to all but for the price a skilled area of this earphone, you get a good sense of instruments separating and even ticking in time together with the correct tracks. I would even say the amount of separation is slightly stronger then my main reference IEM in this price range, Fidue A83. I was impressed with this area.
    There is decent width but not a completely strong point, you won't feel anyway closed into the presentation and from my experience the sources used will completely alter this. I don't however perceive much depth from FLC8 it does sound a little flat in the center channel but most certainly not something that's going to draw your attention or distract you.
    Remembering I've only gone through one option of filters I really can't fault the sound I heard, it was on the brighter sound for those who like lean tonality and It does perform well. The accessories and build are nice, the entire idea of bringing such a customized earphone to the market in itself a great thought. The only real problems I can mention are the fit issues I experienced and the possibility of losing the filters, they're so small and fiddly to set up. I think while adjusting is fun many will find the correct set up for their personal preference and stick with it.
    I see lots of potential in the concept and its obvious appealing to the masses as the Head-fi thread for this earphone is well populated and healthy. Many members are completely happy with the performance and then some more. For me FLC8 won't become my every day earphone because I have those fit issues and personally I still lean a little towards Fidue A83 in this price range. At the end of the day, FLC Technology produced something different, unique, a one off of their own, and that's the beauty of FLC8.
    I'd like to thank FLC Technolgy and @DJScope for arranging the tour!
      casanova, Brooko, djvkool and 6 others like this.
    1. View previous replies...
    2. Skullophile
      H2O how is the imaging of the flc compared to a83?
      Skullophile, Apr 28, 2016
    3. H20Fidelity
      @Skullophile I'd say they're very close as I didn't notice one pull away heavily in imaging. @Signal2Noise This was a tour unit, I've placed it in the only FLC8 review section on Head-fi, sorry for any mic up. Hope you enjoy yours soon! @woye263s personally I still prefer Fidue A83 over FLC8 and I'm yet to find another in the mid-tier IEMs that performs quite as well. DN-2000J or the newer model might also be worth considering
      H20Fidelity, Apr 29, 2016
    4. Arsalan
      Thanks, which one would you buy? DUNU 2002 or FLC8s?
      Arsalan, Aug 8, 2016
  9. sandman1990
    Hidden Gems
    Written by sandman1990
    Published Feb 27, 2016
    Pros - Sound, Build
    Cons - Microphonics
    [Update] 19-Mar-2016 Added comparisons
         I have had the FLC8S for about 3 months but never had the time to sit down and write a review until now. Before proceeding further, I would like to thank all the reviewers and fellow Head-Fi members from the FLC8S thread [link] who initiated my interest in this product.

    7ofR4dc.jpg   W6aDsMS.jpg
    hmE3PC8.jpg   2wlfqqf.jpg
    The IEMs and the Tuning Filters
    1 Preliminaries  
    1.1 About Me
         I am a student in pursuit of a master's degree. I got interested in audio equipment rather recently. I am not the usual reviewer and I have spent most of my time here lurking around looking for answers. So, please pardon me in case some things are out of place. In any case, I am looking forward to feedback from the community to try and improve things in the future. The opinions that I have provided in this review are purely based on my listening experience and not any graphs or numbers.

    1.2 Preferences
         I like a balanced sound signature with good detail reproduction. I have a slight tendency to like bright-sounding headphones as long as they are not too harsh or sibilant. As far as musical preferences go, I am a bit of a metalhead.
    2 Product Overview
         The FLC8S is a triple driver hybrid IEM with a unique tuning system that allows one to tweak the base sound signature in 36 different ways through the use of different filters. On each side, there is a single 8.6mm dynamic driver and dual balanced armature drivers. It has been some time since the original FLC8 became available online. The current iteration, the FLC8S, comes with braided cables.
    2.1 Packaging and Accessories
    The following accessories are included as a part of the standard packaging.
    • Two sets of silicone tips in SS/S/M/L sizes.
    • Three sets of ultra-low and low frequency filters.
    • Two sets of mid-high frequency filters.
    • A 3.5mm to 6.5mm adapter.
    • A balanced to 3.5mm adapter.
    • A cleaning tool.
    • A keychain with a fob that houses the filters.
    • A metal case.
    • A pair of plastic tweezers.
    • An instruction manual.
    2.2 Design and Fit

         I liked the way the box opens up. The materials aren't anything exotic. Everything is rather well organized inside the box. The compact manual has most of the details about the tuning system. The included metal container is very solidly built. So is 6.5mm-to-3.5mm adapter. Each of the two sets of tips, one clear and the other gray, come in SS/S/M/L sizes. The quality, quantity and variety of the supplied tips are pretty decent. The filters are neatly housed inside the keychain's fob. The bass filters are rather tiny and delicate so they might need an extra bit of care when swapping parts. This makes the inclusion of an extra set of the ultra-low and low frequency filters somewhat relieving. The filters, once attached, all sit firmly in place. The IEM housings are lightweight and well-built with decent finishing. The cable is a bit too stiff though. The 2-pin connectors require a bit of effort for removal but nothing herculean. Also, since they have been confirmed to be TF10 compatible, there should be lots of options for those looking for cable upgrades.
         The only major gripe that I could have of the FLC8S is the cable's proneness to microphonics. Also, for people with small ears, the IEMs stick out a bit and it becomes a little difficult to get the stiff memory wire to settle down properly. When it comes to the chin slider and y-split, I want something sturdier instead of simple plastic sleeves. Apart from these, I have no other issues with the fit and isolation.
    2.3 Tuning system
         There are three different types of filters for sub-bass, bass, and mids and highs adjustment.
    • Ultra-low frequency (ULF) filters
      • Clear - Minimum
      • Grey - Medium
      • Red - Maximum
    • Low frequency (LF) filters
      • Clear - Minimum
      • Grey - Medium
      • Black - Maximum
    • Mid + High frequency (MHF) filters
      • Blue - Medium + Minimum
      • Black - Medium + Medium
      • Gold - Maximum + Medium
      • Green - Medium + Maximum

    3 Testing
    3.1 Setup
         For this review, I used a FiiO X3 1st Gen + E12A stack as the source. The X3 was connected to a PC as a USB DAC. For playback, foobar2000 with the proper ASIO drivers was used. Prior to writing this review, I had already used the IEM for over 200 hours.
    3.2 Sound Quality
         Coming from the GR07 and VC1000, both of which are fantastic units from VSonic, when I listened to the FLC8S for the first time I was rather impressed. It offered better mid-range and treble quality compared to the GR07 and better bass, both quality and quantity-wise, than the VC1000 whilst matching or even improving on its mid and highs. At first, the highs sounded a bit metallic but I think with time, it now sounds much more natural. I started listening with the stock M sized tips and a pair of M sized SpinFit tips before reviewing. For this review, I used the stock tips.

    3.2.1 Lows
         With the dynamic driver taking care of the bass, the decay is very natural; neither too fast nor too slow. There is enough impact and control when needed and it goes pretty deep too. Quantity-wise it is a little above neutral with the default Grey ULF, Grey LF filters. The combo of Red ULF, Black LF filters offers the maximum bass. Even in this configuration, the mid and high frequencies are still clearly audible. I was particularly impressed with the way it managed to keep up with the fast-paced bass of some death 'n' roll tracks. It also managed to keep the chilling atmosphere in some raw black metal tracks without adding any noticeable warmth. It really shows the level of control that is on offer. Initially, I often switched between the Grey ULF, Grey LF combo and the Red ULF, Gray LF combo and ended up preferring the former. The Red ULF filter adds a little more impact but I found the Grey ULF filter to be satisfying in most cases.
    3.2.3 Mids
         Throughout the review process, I used either the Black or the Gold MHF filters. I felt that the Green MHF filter affects the naturalness of the vocals. The Blue MHF filter seems to make the sound dull and less energetic. In most cases, I ended up preferring the Gold MHF filter. It makes the mid frequency feel a little more present and sound forward compared to the Black MHF filter. With the Black filter, the mids are smoother but the Gold filter provides a bit more detail retrieval.
    3.2.4 Highs
         The high frequencies sound crisp and energetic without any noticeable sibilance issues with the Black and Gold MHF filters. The Blue MHF filter cuts down the treble presence while the Green MHF filter introduces some sibilance. For classical-inspired instrumental pieces though, I sometimes found myself reaching for the green filter. The speed, decay and airiness are all top notch. Acoustic guitars are a joy to listen on this.
    3.2.5 Soundstage and Imaging
         There is enough width and depth with atmospheric tracks. Everything feels well placed. The layering and separation on offer are very good.
    4 Comparisons
    4.1 VSonic GR07 Classic
         The GR07 has served me well for over 2 years now. In comparison to the GR07, the FLC8S offers more sub-bass, much more mid range presence and far less splashy treble. There is more detail, naturalness and refinement with the FLC8S. Also, the soundstage of the FLC8S has more 3D feel compared to the flatter, 2D-ish feel of the GR07.
    5 Conclusion
         I must admit that I highly impressed by the performance of these hybrids. For me, they score top grades in almost every department when it comes to the sound. Coming from sub $150 IEMs, I cannot really comment if the FLC8S truly delivers top-tier performance, but, I am pretty sure that its the best pair I have owned and listened to till date. Being on a student budget, it was a considerable investment for me but I must admit that I am thoroughly satisfied. For anyone looking to make the jump to next tier from the sub $150 realm, I think a pair will not disappoint.

      Brooko, Hawaiibadboy, DJScope and 3 others like this.
    1. View previous replies...
    2. hqssui
      Great review, thanks
      hqssui, Feb 27, 2016
    3. sandman1990
      sandman1990, Feb 28, 2016
    4. sandman1990
      Added a comparison with the GR07
      sandman1990, Mar 19, 2016
  10. kamcok
    This belongs in summit-fi if it was made by a bigger brand
    Written by kamcok
    Published Nov 24, 2015
    Pros - The sound. THE SOUND !!!!!!!! Hi-Res without the sticker
    Cons - cable can be improved, easy to lose tuning parts, isolation is good not great
    First of all I only had like one week to try the IEM and finish this review so take it with a grain of salt.
    I also didn’t have time to take photos so I’m really sorry that this is just a pure text review :frowning2:
    Have you heard of the FLC8S ? No ?
    What about the company that made it, FLC Technology ? No ?
    Well neither had I before DJScope asked me to join the Australian tour of it.
    Just to clear things up, I’m not associated with FLC technologies in any way. The review unit was sent to me by Djscope and I am not sponsored or endorsed by anyone in any way.
    I’ve always seen the IEM on the Singapore based Lend Me Ur Ears online shop, but I have always dismissed it. I didn’t even look at it for more than 1 minute as I thought it was much overpriced for an ugly earphone made by an unfamiliar company. Even more, the tuning system of interchangeable nozzle and two of its plugs made it seem complicated and gimmicky. 
    Boy have I never been more wrong.
    Let’s start with the fit and finish.
    The 8S is pretty much all dark blue in colour, all the way from the jack, to the ear tips, the body may seem black but under proper lighting it is actually a very dark blue finish. The cable is braided and is held together by a very plain and simple plastic sleeve for the Y-split. The same plastic is used for the chin slider and this is where I would take a point off the build quality. To me, this plastic sleeve is simply inadequate and may not last for very long.
    The cable on the earphone is quite soft but is a bit springy but nowhere as springy as that of the FiiO EX1. I quite like the cable’s look and feel to be honest but I do notice that the cable does cause quite a bit of microphonics. So far, I’ve mostly used the IEM when I’m sitting with my laptop so I’m not so sure how it will handle when used while walking.
    The cable is connected to the body by a 2-pin connector that holds on securely but will not be a struggle to remove. The connection is flush with the body making it appear as a part of the body itself. Just from the looks I didn’t even know that the cables were removable.
    The actual IEM housing is very well built, the plastic quality and the finish is on par with the big brands such as shure / westone. It's solid, smooth and doesn't get easily scratched.
    It is definitely superior than low grade chinese IEMs such as RE-400 / VSD series by Vsonic and etc. 
    The quality of the accessories is… fairly good. The interchangeable nozzle seems very durable but the low frequency plugs are very small in size. Not that I’m afraid of breaking the plugs but I can see people losing them. It’s a nice gesture that they include spares but it is still a bit of an issue. Plus, due to the small size it makes changing the plugs almost impossible without a clean, still surface.
    The sound quality of this IEM is simply superb, but due to time constraints as I only have one week to listen and write a review for it, I cannot describe each any every tuning characteristic in too much detail.
    In general I’m utterly impressed with this IEM. I strongly encourage those who have yet to try to give the FLC 8S a chance.
    For the highs, the fitting of the interchangeable filters should be carefully chosen to match the type of music prior to listening for the best experience. The difference in presentation of the filters is quite significant and when an incorrect filter is used, certain music genres can sound undesirable. The use of green filter for example would be far too bright for pop / rock songs, making them sound splashy and sibilant, but when used for classical songs can make them sound extremely detailed spacious and airy. The opposite is true when using the reduced high frequency blue filter, it makes energetic songs with lots of hi-hats and cymbal hits sound easier to listen to but makes classical and vocal-centric music sound a tad dark and lacking in air.
    Included in the package are 2 more filters, the gold (mid centric, normal highs) and the black (normal mids, normal highs). I find that the black (default/neutral) filter is the most versatile in that it can be used for most music genres.
    Extra notes: the highs presented by the IEM is also variable depending on the ear-tip of choice. I find that using the JVC spiral dot tips made the highs more prominent making it a bit too bright/ harsh for me. So far I find that using the TX-400 Comply tips gave me the most ideal presentation.
    The mid-range is absolutely fantastic on all of the settings. Just be wary that the tuned down HF filter can affect the upper vocal region slightly making female vocals sound a tad darker/ nasal. The mids in general is crystal clear with superb resolution and is well layered. Each component of the music is very well separated. I even noticed that for the first time I was able to follow the notes and not just hear the fourth guitar on Ecosystem’s Dilemma. Even songs that I considered to be “low-resolution” sound much more pleasing than normal.
    The bass presentation can vary from just north of neutral on the lowest setting, reaching still very deep. This allows listeners to focus more on the mid-range and high frequencies suitable for vocal centric songs. However, even on the highest setting it still sounds natural and controlled, still no bleed to other regions. I left my setting on the highest no matter what music I listen to because the IEM is capable of such high degree of control. It doesn’t make an unnecessary boom / veil when uncalled for. The bass comes in only when it’s needed and is so high in resolution that it makes the CKR9LTD which I considered to be one my best to seemingly sound muddy in comparison. In the manual it is recommended that for vocal songs that the bass filter is changed to the clear (lowest) one, but to me, this only reduces the richness of the song. Again as I’ve said earlier, even on the black (highest) bass filter, the mid-range is still crystal clear.
    The bass is to me, characteristic of a very well tuned dynamic driver, having just the right amount of punch and rumble while staying in control. Often, however, such single dynamic drivers is compromised in the upper frequencies at the cost of having amazing bass. The FLC8S doesn’t suffer from this as it is a amazingly tuned hybrid 1BA 1dynamic earphone.
    The soundstage ! The soundstage makes songs very immersive, it produces an out of the head experience with each musical component placed not just in a 2 dimensional (wide) presentation but is capable of making music sound truly 3 dimensional (deep and wide). I have listened thoroughly through songs that I would normally skip, as songs that are not even in my preferred genre sound mind blowing. It makes me appreciate every song in my library, which is really something that no audio product was capable of.
    All of these in addition to the great fit of the IEM makes it all the better. It simply fits. I can’t elaborate too much on this; the curvature of the IEM matches so well with the ear. Once you put it in it just stays there and you’ll forget you will hardly notice its presence.
    Note that the IEM doesn’t stick out, but you still can’t sleep on your side with this IEM.
    In conclusion the FLC8S is an astounding IEM capable of producing sound in high degree of resolution. The tuning system is a huge bonus that allows users to tune the FLC8 to suit their music genre of preference. The soundstage and technical capabilities of this IEM even without the tuning system is enough to distinct this IEM from the others. Despite this, the FLC8 can be improved with a softer, less microphonic cable and the tuning system isn’t perfect as small parts can be lost easily.
    Pro: rich yet natural sound, considerable as truly hi-res without the sticker, comfortable, tuning available to suit preference
    Cons : easy to lose bass tuning plugs,  cable is microphonic, expensive-ish
    If you have the money, buy it, give it a shot, seriously
    This made me top picks (Aurisonics rockets and CKR9LTD) sound "meh"
      soundstige, d marc0, JoeDoe and 3 others like this.
    1. View previous replies...
    2. Flcforrestwei
      Thanks Kamcok! Great review! I'm Forrest Wei, designer of the product.
      The cable was braided by a special machine me designed, I can say that the cable is very unique, almost all cable with the same contruction need to be cut in the middle and joint together at the Y split, but our cable doesn't have the solder joints, the signal is not interrupted, better to the sound.
      The "plastic" at the Y split is not plastic, it's heat shrink tube, it's very strong, please do worry the quality.
      Flcforrestwei, Nov 25, 2015
    3. soundstige
      I bit. My review will be coming in a few days.
      soundstige, Nov 29, 2015
    4. kamcok
      Thanks to all those who read and enjoyed the review.
      As im on my phone i cant tag people fyi.

      @Soundstige, joedoe hope you enjoy the iem as much as i did
      @redtwilight, whaleshark12, thanks for pointing that out, i will edit it once im back from my trip

      @flcforrestwei, i am impressed with youe product and i would definitely recommend it. I trust that cable and the y splitter is durable as you said. I dont have any problems with it, just stating some things that others may not like. I think you can somehow make the splitter easier to slide and make the cable softer so it will be less microphonic.

      Even for those who cant stand the cable, its not difficult to find an aftermarket product to suit your liking
      kamcok, Nov 30, 2015