FLC Technology FLC 8S

Average User Rating:
4.47059/5,
  1. Hisoundfi
    4.5/5,
    "Choose your own adventure... The FLC 8S triple driver hybrid in-ear monitor with tuning filters"
    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.
     
    https://www.amazon.com/s/ref=sr_nr_p_4_4?me=A453POZ0FLKWP&fst=as%3Aoff&rh=p_4%3AFLC&ie=UTF8&qid=1490650093
     
    https://shop.musicteck.com/products/flc-8s-hybrid-dual-balanced-armature-dynamic-earphones
     
    Introduction
    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.
     
    Disclaimer
    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.
     
    Review

    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

    Specification:
    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
     

    Accessories:
    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.

     
    Functionality

    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:
     
    [​IMG]
     
    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.
     
    Conclusion
    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!
    tarhana, meringo, MidFiMoney and 8 others like this.
  2. FUYU
    4.5/5,
    "Triple Hybrid done right! - The FLC8s"
    Pros - Incredible imaging; clarity and resolution; Tuning options
    Cons - That cable; small tuning filters


    Over the course of this year, I have noticed that my enthusiasm about buying new gear has become rather stagnant. Ever since I started my personal audio-journey in 2014 and many listening sessions later, nothing excites my now veteran ears anymore. To my surprise came FORREST and renewed my childish side with their announcement of the FLC8s. I have been following the FLC8 Thread for quite some time now. And while the FLC8s are available since November 2015, I never pulled the trigger. Until now...

    Enter FLC8s by FORREST.

    Disclaimer: I bought these on Shenzhen Audio for 269$. I'm not affiliated with FORREST or Shenzhen Audio in any shape or form.

    About me:
    My name is Noel aka. FUYU, I'm 19 years old and an avid lover for everything technical.
    While everything is subjective, I like to explain in more rational enclosure with graphs and technical prowess. I care about facts and only facts, meaning no fancy 300$ cables and value by price-to performance.

    Specifications:


    • Type: Hybrid dual BA + 8.6mm Dynamic Driver
    • Frequency Range: 20 Hz – 20 kHz
    • Impedance: 11 ohm
    • Sensitivity: 117 dB @ 1kHz 1mW
    • Cable: 1.2m 4 core single twisted copper (replaceable)
    • Jack: 3.5mm gold plated, straight jack
    • Weight: Approx 14g with tips in place
    • IEM Shell: Hi-gloss strengthened plastic


    Accessories:





    The FLC8s comes in a rather large box for an IEM. Don't be fooled however! This is not due to the IEM itself, but the quite stellar set of equipment and its very unique presentation. Using a folding mechanism reveals two compartments, both protected in thick blue coloured foam. The first layer contains the IEM, while the second layer retains the carrying case and filters with included tweezers. A+ FORREST!

    The included metal carrying case, while not so transportable, will protect your FLC8s or IEM of choice against all kinds of hazards. That thing is literally undestroyable. Reminds me of those old Nokia Cellphones back in the day...

    Opening up the carrying case reveals an airline adapter, a 3.5mm to 5.3mm adapter, a cleaning tool coupled with some tips. Everything you need.

    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.

    Build and Design:




    The FLC8S is made in a high gloss plastic shell, and at first glance you'd think it was made of polished coloured aluminium. Each earpiece is very ergonomic – designed to fit the contours of the ears, without feeling heavy or having sharp edges. The two piece plastic shell looks very sophisticated, coming in either blue or red colour.

    Dimensions are on the moderate side with 18mm x 10mm x 18mm. The body is S-shaped, and the nozzle is perpendicular to the main body. I didn't encounter any major issues with fit, but I can envision it not being ideal for everybody's ear-type. Although it is a vented design (replaceable nonetheless), Isolation is actually above average for most In-Ear designs. Commuting is very acceptable with some adjustment to your listening volume.

    The biggest shortcoming of the FLC8s is the included cable. While it has lost the big 7,5cm chunk of memory wire in newer revisions, it is still rather unruly and tangles a lot. Furthermore it has in probable amounts of microphonics, making it unsuited for heavy-duty activity.

    Luckily the FLC8s features a very stable 2-pin connection. The sockets are raised, with the cable plugs fitting snugly over the top for added strength. The FLC8s uses the UE standard.

    Sound-Analysis:

    Filters - Usability and general Impressions:

    The filters are divided in to three brackets:

    • ULF - Ultra-Low-Frequency - Sub-Bass
    • LF - Low-Frequency - Mid-Bass
    • MF/HF - Mid and High Frequency

    The experience which defined my time with the FLC8s. I love tinkering with things, but my fingers are pretty large (I can easily palm a Size 7 Basketball). The MF/HF filters are easy to replace by unscrewing them from the nozzle. However, inserting and removing the ULF/LF filters was frustrating and took lots of fiddling and patience. I even lost a black LF filter to the carpet - beware!




    (For some proper measurements please refer to Brooko's review here)

    General observations:

    • Clean sounding with lots of micro-detail
    • Imaging is precise and with good airiness
    • Coherence is fantastic even with Red-Black filters in place
    • No glaring sonic weakness
    • Lower midrange is not affected by tuning
    • Extension on either side of the spectrum is fantastic

    Don't expect the FLC8s to be the jack-of-all-trades. It has a base signature which is retained over all filter combinations: A bright, but organic sounding In-Ear. It is not going to sound warm or even bassy. Think of it this way:

    The FLC8s is not a tunable IEM with great sound. The FLC8s is a great sounding IEM with tuning options.

    Pairing:

    • 11Ohm and 114dB/mW makes for easy listening out of your smartphone
    • Amping is absolutely not required
    • The FLC8s profits from warmer sources

    Some Filters combinations:




    Red-Clear-Grey:

    The RCG combo is my personal favorite and suits my preferences best with its slight U-Shape signature:

    Bass:

    • Overall very balanced sounding with some slight tilt towards the lower echelons adding some rumble to the mix.
    • Neutral sounding mid-bass. Zero bass-bleed into the midrange.
    • Highly detailed bass response, good texture.

    Mids:

    • Lower Midrange is slightly recessed, thus improves the spacial presentation.
    • Organic sounding with some moderate brightness.
    • Soundstage is moderately sized in all three directions. Appears spherical with center position.

    Treble:

    • 5kHz area is slightly recessed.
    • Moderate rise around 7kHz, giving the FLC8s some sparkle without getting fatiguing

    Red-Grey-Gold:

    The RGG combo was the first combination I have listened to. I don't enjoy the Gold filters all that much. The RGG variant works well with modern genres.

    Bass:

    • Overall more impact with extra energy
    • Focus on Mid-Bass. Plenty of bass. Although Bass-Heads might be left wanting.
    • Retains the same clarity and coherence.

    Mids:

    • More upper-mid focus around 3kHz compared to the Grey filters
    • Forward sounding female-vocals
    • Soundstage appears to be smaller
    • Overall brighter sounding

    Treble:

    • Identical sounding, but balance has shifted.
    • Loses some airiness.
    • Detail retrival is the same.

    The green and blue filters are too extreme for my tastes. The former is too peaky in the 7kHz area , whereas the latter sounds too muted and rolled off. I can safely say that the FLC8s works with almost any genre and excels with classic in particular.

    Comparison with the Trinity Phantom Master 4:

    The Master 4 is overall warmer and more inviting sounding compared to the FLC8s. The FLC8s is less spacious sounding, but more precise in terms of imaging. Bass is much more evident on the PM4, with authority which simply cannot be matched by the FLC8s, albeit at the cost of sounding slighly bloated. Instruments are easier to depict with the FLC8s. Furthermore due to the smaller soundstage, the FLC8s has an easier time diving into the individual aspects of songs and music. The FLC8s has better detail-retrieval overall. The PM4 has more mid-bass and lower midrange emphasis, which makes it warmer and more "fun", whereas the FLC8s is generally more neutral and linear in presentation. My personal preference goes to the FLC8s. The PM4 has too many sonic weaknesses compared to the FLC8s, in particular in the upper-midrange to treble area. FORRESTs offering has better realism, more linearity and more technicality.

    Final Words:

    I really enjoy the FLC8s. For around 300$, you get an all-around package, which will keep you up at night for many months to come. While it is not perfect, the versatility you get for the asking price is well worth it. Flcforrestwei good job! Looking forward to the Celeste.
  3. Brooko
    4.5/5,
    "FLC8S – Versatility to the Extreme"
    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
     

    INTRODUCTION

     
    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.
     
    ABOUT FLC
    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.
     
    DISCLAIMER
    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)
     
    PREAMBLE - 'ABOUT ME'. 
    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 REVIEW

     
    PACKAGING AND ACCESSORIES
    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”.
     
    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.
     
    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
       
    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.
     
    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.
     
    TECHNICAL SPECIFICATIONS
    (From FLC)
     
     
    FLC8S
    Type
    Hybrid dual BA + 8.6mm Dynamic Driver
    Frequency Range
    20 Hz – 20 kHz
    Impedance
    11 ohm
    Sensitivity
    117 dB @ 1kHz 1mW
    Cable
    1.2m 4 core single twisted copper (replaceable)
    Jack
    3.5mm gold plated, straight jack
    Weight
    Approx 14g with tips in place
    IEM Shell
    Hi-gloss strengthened plastic

     
     
    BUILD QUALITY / DESIGN
    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.
     
    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).
     
    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.
     
    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.
     
    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.
     
    Y-split and cinch
    Jack
    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.
     
    FIT / COMFORT / ISOLATION
    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.
     
    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.
     
    FIRST IMPRESSIONS - USABILITY
    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
     
    FILTERS AND FREQUENCY GRAPHS
    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.
     
    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.
     
    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:
     
    Filter
    Colour
    Effect
    ULF
    Red plug
    Most sub-bass
    ULF
    Grey plug
    Medium sub-bass
    ULF
    Clear plug
    Least Sub-bass
    LF
    No filter
    Most mid-bass
    LF
    Black plug
    Medium/high mid-bass
    LF
    Grey plug
    Medium/low mid-bass
    LF
    Clear plug
    Least (flattest) mid-bass
    MF/HF
    Gold bore
    Most MF and medium HF
    MF/HF
    Green bore
    Most HF and medium MF
    MF/HF
    Black bore
    Medium MF and medium HF
    MF/HF
    Blue bore
    Least HF
    MF/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.
     
    AMPLIFICATION REQUIREMENTS

    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.
     
    EQUALISATION
    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.
     
    SOUND QUALITY
    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.
     
    COMPARISONS
    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)
    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)
    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)
    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.
     

    FLC8S - SUMMARY

     
    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.
     
     ​
    APPENDIX
    The following graphs are my measurements of Forrest's default recommendations.  They show some of the versatility of the FLC8S:
     
    Clear, clear, gold = vocal
    Grey, black, gold = pop/rap
    Clear, clear, green = piano or strings

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

     
  4. twister6
    4.5/5,
    "Custom Tune the Sound, just the way YOU like it! FLC 8S Custom IEM Review"
    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.
     
    Unboxing.
     
     
     
     
     
    Accessories.
     
     
     
     
    Cable.
     
    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.
     
     
     

     
    Design.
     
    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.
     
     
     
     
     
    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.
     
     
     
     
     
    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.
     

     
    Conclusion.
     
    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.
  5. H20Fidelity
    4.0/5,
    "Great concept, great Idea"
    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! 
     
     
    Specs:
     
    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)
     
     
    Pricing:
     
    1. $349 USD (found at lendmeurears.com and other selected vendors)
     
    http://www.lendmeurears.com/flc8s-red/
     
     
     
    Packaging:
     
    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.
     
     

     
     

     
     

     
     
     
    Build:
     
    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.
     
    Accessories:
     
    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:
     
     

     
     

     
     

     
     

     
     
     
     
    Sound: 
     
    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
     
     
     
    Bass:
     
    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.
     
    Mids:
     
    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.
     
    Treble:
     
    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!
     
    Separation:
     
    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.
     
     
    Soundstage:
     
    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.
     
    Conclusion:
     
    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.
  6. HiFiChris
    4.5/5,
    ""36 Faces of a Modder's and Tweaker's Delight" -or- "Flagship Performance for a Mid-Fi Price""
    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


     
     
    Preamble:

    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.
     

     
     
     
     
     
     
     



    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.

     

    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.

     
     

    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).
     

     
     



    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.


    Sound:

    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.

    Tonality:

    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:
    ULF
    LF
    MF/HF
     
     
     
    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-Filters:
    (ULF Filter  I  Grey  I  Gold)




    LF-Filters:
    (Grey  I  LF Filter  I  Gold)


     

    MF-/HF-Filters:
    (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.

    Resolution:

    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”.

    Soundstage:

    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.


    Conclusion:

    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.
  7. kevingzw
    4.5/5,
    "A Diamond in the Rough"
    Pros - Unbelievable Coherence, Distinct Airiness, Endless Customization/Tunable Options, Lightweight and Solid Construction, Aluminium Carrying Case
    Cons - Tuning Ports/Filters are fragile, Tedious Tuning
    Before I start on my endless tirade on this hidden gem, allow me to make a formal introduction.
     
     
    My Formal Introduction
     
    I'm a 19 year old (coming 20) Singaporean Student waiting to serve my Mandatory Army Service. I grew up captivated by music and its divergent genres. From subversive punk (The Germs, Black Flag) to the Mellow Jazz Cats (Miles Davis, John Coltrane), I was always fond of music history and the preceding factors that led to the formation of several bands and genres. Ever since my brother brought me to Jaben in its glory days (in a crummy, old warehouse with a pile of imported iems), I started to stick my itchy fingers into the personal audio market. I'm no audiophile, but I'm just here to give my two cents on products that I find far more than capable at a suitable price. I despise the lifeless sound of a Balanced Armature on its own. The unnaturally faux left to right soundstage and the rigid/dry bass response always irked me. Hybrids and Dynamic Drivers will and always be the top tier transducer/combinations in my heart. 
     
     
    Alittle Bit of Backstory
     
    FLC Technology is a company based in Guangdong, China. Opened by Forrest Wei (correct me if I'm wrong), a industry regular that has worked with the likes of UE and Jabra, the FLC 8 is their first foray into the Universal IEM Market. Launching their first CIEM in 2011, FLC Technology hopes to make a name for itself in a congested IEM Market. The FLC 8S is an exact cut/copy replica of the FLC 8, provided with a 4-braid SPC Cable instead of the poorly sheathed cable by its predecessor. Forrest believes that the consumer should have a say in the sound signature of any IEM, hence the provision of tunable filters.
     
    The FLC 8S is a hybrid in-ear monitor, with a 2 Balanced Armature + Dynamic Driver (3 Way Crossover) configuration. The FLC 8S boasts a whopping 36 tunable options, setting itself apart from the competition. China is making a name for itself in an already crowded IEM market dominated by the big three (Shure, Audio Technica and Westone). I'm proud to report that the FLC 8S is a top tier contender that blows the competition out of the water. They are a diamond in the rough, a hidden gem waiting to be discovered.
     
     
    Build Quality/Accessories
     
    Right off the bat, the lavish wooden box looks downright expensive. FLC definitely went out of its way to package the product beautifully. Inside the box, we have several eartips (S,M,L), a anodized aluminium rounded case (this sh*t is built like a tank) and a keychain carrying the different filters and nozzles. The accessories provided are impeccable and feel almost premium, rivaling the likes of the Shure SE846. Gotta give a shoutout to FLC for giving us a premium package at an affordable price point.
     
    Moving on to the IEM's, they look almost alien-like. The driver-housing or the actual body of the IEM's are shaped like curved S's, with a glossy finish. There are several ports or tiny holes to allow the user to interchange filters and try out a variant of sound signatures. Apart from the outlandish appearance (at first), the IEM's are feather-light with negative profile. The flushed fit and lightweight housing provided me with a comfortable listening experience. It's as if the FLC 8S melds with the ear to become a unified body. I've used them for over 3 hours straight with no signs of discomfort or fatigue. They feel solid in the hand and I have no doubt's that they were built to last for a long time.
     
    The cable termination is a recessed 2 pin connector (the UE Triple -fi connectors), which are easily user replaced. Having said that, the stock 4-braid SPC cables provided marked a significant improvement compared to its predecessor, which provided a rubber-sheathed cable with stiff strain reliefs and a bad tendency to clump into a giant ball. They are easily pliable and the memory wire offsets the weight off the IEM onto them, acting as a strain relief.
     
    I have to say, I am duly impressed by the overall build and accessories provided.
     
     
    Sound Quality
     
    I have to say, these IEM's are absolutely stellar. Admittedly, these are IEM's are ever changing chameleons, with 36 tunable options that leaves the user baffled by its ability to adapt. I for one, value my time and choose not to review every single combination. Having said that, the combination I have utilized centers around a heavy low end, distinct mid range and medium high frequency (minor filtering). Do take note that the tuning process has a steep learning curve. Time and patience must be exercised to find a suitable combination that meets your tastes. Its time for me to dive head first into the delicate art of finding the right "sound".
     
    [​IMG]
    Credits to Lendmeurears for the image
     
    Nozzles
    - Black Filter: Medium Mid Range and High Frequency
    - Green Filter: Medium Mid Range and Most High Frequency
    - Blue Filter: Medium Mid Range and Least High Frequency 
    - Gold Filter: Most Mid Range and Medium High Frequency
     
    Rubber Stoppers (white, black grey)
    - White Stopper: Medium Bass
    - Clear Stopper: Least Bass
    - Black Stopper: Most Bass
     
    Rubber Thumbtacks (lol)
    - Clear: Least Subbass
    - Black: Medium Subbass
    - Red: Most Subbass
     
    As you can see, the art of finding the right sound can be tedious. It makes for a fun project though. Be wary that the intricate filters are tiny and easily lost. Thankfully, Lendmeurears Singapore stocks replacement filters at a reasonable price.
     
    As of now, I'm utilizing the Gold Nozzle => Black Stopper => Red Thumbtack Configuration. It focuses primarily on a creamy mid range, smooth highs with ample detail and a airy bassline. 
     
    The FLC 8S left me floored. Balanced Armatures are known for their distinctly sharp mid range, extended highs and accurate/rigid response. The addition of an 8.6mm Dynamic Driver offsets the weaknesses of the 2 Balanced Armatures by providing a robust bassline and superb subbass decay. What boggles my mind is the coherence of it all. I believe that transient smearing and the use of 3-4 balanced armatures with no dynamic driver results in an incoherent, artificial sound that feels vastly separated. The unnatural left-right channel separation (faux soundstage) and crummy low-end response doesn't leave me satisfied. This is certainly not the case for these hybrid badboys. 
     
    The Gold Nozzle tames the highs and smoothens the peaks, but it does it in such a way where the highs aren't sibilant and provide just enough detail. With tracks such as Charles Mingus's Moanin, the baritone saxophone barely loses detail and in fact sounds almost natural (apart from minor smoothing)
     
    The Midrange is rich, easily distinguishable and detail heavy, with a non-fatiguing wet sound that avoids the harsh trebles and sharp mid-ranges commonly associated with balanced armatures. It provides for a non-fatiguing listen for any genre. It's even listenable with the sharpest of treble-heavy genres such as Hardcore Punk. That is an achievement on itself.
     
    The low end is the highlight of the FLC 8S that separates the men from the boys. Using the Black Stoppers and Red Thumbtacks, the sumptuous low end proves to be well controlled, with a tight midbass response and sublime subbass decay. Most importantly, the bass in my opinion, doesn't bleed into the mid range at all, leaving us with a fun/controlled bass response that faithfully captures the air and stage presence of any given recording.The FLC 8S is a forgiving IEM, even with 128kbps MP3 Files.
     
     
    In Conclusion
     
    The FLC 8S is a representation of Chinese innovation. Over the years, I have seen the growth of many a Chinese Audio Company, each trying to tap into the Southeast Asian market. Some companies left me impressed (Vsonic, Havi) but nothing blew me away. The FLC 8S has done just that. Their penchant for perfection in sound, build and customization is a testament to Chinese quality. I would've given them a perfect score, if not for the fragile tuning components. I certainly hope that people give the FLC 8S's a shot and be mesmerized by their sound.
    Dopaminer, B9Scrambler and hqssui like this.
  8. originalsnuffy
    4.5/5,
    "Detailed, open sound. Massively customizable. "
    Pros - Sound can be fine tuned to listener preference. High fidelity at reasonable price point.
    Cons - Difificult to insert filters. Easy to lose filters. Moderately easy to get ear fit but not dead simple. Tuning could be "overkill" for some.
    I had the pleasure of listening to the FLC8S for about 10 days. 
     
    I listened to these on a FIIO X3 Gen II, a Shanling M2, and the venerable iphone 6S.   My comparison is to LZ-A2 using Comply foam tips, Phonak Audeo PFE-022 with black filters and Comply foam tips, and Carbo Tenore using stock tips. 
     
    I listened to a wide variety of music, including Rock, Jazz, and Classical.  Something that surprised me was that I could listen to all varieties of music with these and get a pleasurable experience.  Normally I reserve the Phonaks for classical, where bass is not as important and musical accuracy is important.  But with these I was very happy no matter the source material.
     
    They sounded very good with all players, but were especially terrific with the Shanling M2.  The Shanling is a very neutral and clear sounding unit, and really brought out the best in these earphones.
     
    I found myself noticing the clarity of instruments, yet easy shifted to simply enjoying hi res music.  There is a reason these IEM units have developed a buzz; it is simply not just hype. The detachable cables can come loose fairly easily, so I would be careful with the units when used in public areas.  I stuck mainly to the blue cables though I did try the other two cables that were in box.  Somehow I preferred the blue cable comfort and stuck with those.
     
    My overall conclusion is that these provides an exception level of audio quality with a high degree of customization.   I mainly fiddled with the low bass, as I was very happy with the stock tunings. The effect was subtle but helpful to add sub bass.
     
    It is interesting to me that most other reviewers of this headphone also seem to go with the stock tunings, with the possible exception of adding more sub bass.  That is because these IEM units have an essential “rightness” to them right out of the box.  
     
    Customizing these IEM units is not super easy.  As other have mentioned, the small rubbery plastic inserts are difficult to manipulate and go flying about.  I would suggest working on a clear table and not over carpet.  Pieces can and will go missing.  I ended up using the tweezers to remove the tuning devices but put them in by finger. 
     
    My overall suggestion is that the manufacturer consider offering a cost reduced version of these with the base neutral tunings with the exception of somewhat tweaked sub bass.   I think a more basic version with this sound signature at the right place could become a monster product.  I realize the tunability put the manufacturer on the map, but now that they have a name I would readily purchase a cheaper, less tunable version. 
     
    I would also suggest studying the fit of the Carbo Tenore, which somehow gets the sound right in a very comfortable to wear format.
     
    These are exceptional IEM units and my sense is that improvements on these will ultimately be about fit, comfort, and price and not about sound quality.


  9. d marc0
    4.0/5,
    "The hybrid in-ear monitor with tuning capabilities of up to 36 sound variations!"
    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)



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

    TEST TRACKS:
    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*.

    TUNING ACCESSORIES & HOW THEY AFFECT THE SOUND



     
    RECOMMENDED COMBINATIONS



    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.
  10. sandman1990
    4.5/5,
    "Hidden Gems"
    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.
     

     
     
    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.