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Thumping Bass But Surprisingly Good Midrange

A Review On: Tekfusion Twinwoofers

Tekfusion Twinwoofers

Rated # 159 in Universal Fit
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Pros: Value, IEM build (not the cable), very good mid-range, clarity (despite the bass), comfort

Cons: Cable quality, bass quantity (excessive), driver flex, carry case


For larger views of any of the photos (1200 x 800) - please click on the individual images




Tekfusion (http://www.tekfusiontechnologies.com/) is an audio company founded in 2011 in Bangalore, India.  They are pretty ‘new on the block’, and it was only recently that they appeared on Head-Fi looking for reviewers of their Twinwoofer IEMs. I expressed an interest, and along with four others was chosen to be on the panel of initial reviewers.  As the name suggests, Tekfusion’s Twinwoofers were designed with serious bass impact and resolution as a focus.  Their website notes this about the Twinwoofers:
 “Every beat is important”. This is the principal that lead to genesis of the Twinwoofers®. Their built-in HD dynamic speaker systems yield dynamic bass and a high level of audio precision that gives you a topnotch music-listening experience.


The Twinwoofers arrived a little under a week ago, and since their arrival, I’ve concentrated on getting as much “ear-time” as possible with them – averaging around 5-6 hours a day.  For the burn-in believers (I’m not one), when I haven’t been listening to the Twinwoofers, I’ve given them 3 x 8 hour overnight burn-in sessions – playing a random variety of tracks at slightly louder than my normal listening period.  So between the actual listening and additional “burning” – they’ve had at least 50 hours use.  In that time, I’ve noticed no appreciable change – apart from me becoming acclimatised to their signature.


I’ve listed price at USD $49.99.  I understand that this will be the list price for international sales.  However this is not what I paid for them (they are a review sample).  After completion of this review, I do intend to contact some fellow Australian Head-Fiers so that they also can try these and leave their own impressions.




I was provided the Tekfusion Twinwoofers as a review sample.  I am in no way affiliated with Tekfusion - and this review is my honest opinion of the Twinwoofers I have been sent.  I would like to thank Harry from Tekfusion for making this opportunity available.


PREAMBLE - 'ABOUT ME'.   (or a base-line for interpreting my thoughts and bias)


I'm a 47 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 portable (Fiio X5, and iPhone4) to my desk-top's set-up (PC > coax > NFB-12 > LD MKIV > HP).  My work set-up is the Beyerdynamix A200p (DAC/amp) + whatever fullsized headphones or IEMs take my fancy for the day. My main full sized headphone at the time of writing is the Beyerdynamic T1 (after recently selling my other full sized cans – HD700, HD600 and DT880).  Most of my portable listening is done with IEMs - and up till now it has mainly been with the Dunu DN-1000, Altone200, Brainwavz S5 and RockJaw Alfa Genus. 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 tend toward cans that are relatively neutral/balanced.  I am neither a bass nor treble head (you could argue that I do like clarity though).  I am not treble sensitive (at all), and in the past have really enjoyed headphones like the K701, SR325i, and of course the DT880.


For the purposes of this review - I used the Twinwoofers straight from the headphone-out socket of my Fiio X5, and iPhone 4.  I did not amp them, as IMO they do not benefit from additional amplification.  In the time I have spent with the Twinwoofers, I have noticed no change to the overall sonic presentation (I do not believe in 'night and day' burn-in).  I will respect others choice if they believe in physical burn-in, but I am yet to experience it.


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 Tekfusion Twinwoofers arrived in a black retail outer box (13.5cm x 22 cm x 2.5cm) with clear window.  Inside the box is a moulded clear plastic hinged container housing the Twinwoofers and accessories.


Front of retail box Rear of retail box


For a budget IEM the packaging is quite smart – black, orange and chrome.  I do apologise for the condition of the retail box shown in the photographs.  Unfortunately it arrived in this condition (slightly ‘bruised/creased’).  Luckily there was no damage at all to the contents – which were securely housed.


The retail box has a very simple front – the name, “Black Chrome Edition” (they are also sold in white), and the phrase “Powerful Bass , Audio Accuracy”.  The rear of the box has generic descriptions of the main features of the Twinwoofers along with a description of the accessories.


Inner clear hinged plastic sleeve Twinwoofers + accessories


The accessory package includes a manual and warranty (foldout booklet) – which also includes the published technical data (see table below).  Also included is a shirt clip, soft carry case, and 5 pairs of silicone tips – 3 single flange (S,M,L) and two pairs of triple flange (one narrow and one larger).


Tip selection Fabric carry case - squeeze snap-lock opening


The carry case is a velour type fabric expandable opening snap case which will offer minimal protection, but is handy for storage and carrying the IEMs when not in use.  I personally don’t like these cases because over time the cables tend to get stuck/wedged in the opening.  I had the same thing happen with a case for Monster Turbine.  A far more practical soft case would be something like the zipped case used on the Altone200s I bought recently.



(From Tekfusion)



10mm Single Dynamic


16 ohms


113 dB / 1kHz

Frequency Response

19 Hz – 21kHz

Net Weight


Cable Dimension

1.2m symmetric

Cable Type

Nylon + copper, coated with TPE

Connector type

Gold plated 3.5mm – straight connection.




have requested this information from Tekfusion – but have been advised by their engineers that it is not available for publication at this time.  If it becomes available, I will re-edit the review and add the information later.  For the record – I’m expecting a V shape with bass emphasis (both sub-bass and mid-bass), relatively flat lower mid-range, slightly forward upper mids and lower treble, and relatively quick roll-off in the upper treble.




IEM body and nozzle IEM body and nozzle - good shot of strain relief


The Tekfusion Twinwoofer has a cylindrical hourglass shaped body made from an aluminium alloy.  The body has no obvious seams and appears extremely well machined and quite smooth.  The body measures approx. 20mm in length from the bass to the filter at the tip, and has a diameter of approx. 11mm.  Tekfusion says that the housings only weigh 7.5g each, so they are very light in weight.  The printing on the body of the IEM is very clean and clear (white against black), and it’s pleasing to see L and R marked so that it is easy to read.  The rear plate with the logo is actually a brushed aluminium plate - which has a plastic coating for protection.  This can be removed if it's starts lifting (mine was) - thanks Harry for pointing this out to me :) 


Default tips fitted Foam tips fitted - note lifting on the rear cover - I've since removed it


The nozzle stem is approx. 6mm in length, and the lip is well designed - I’ve had no issues with the included silicone tips, or my preferred foam tips.


The strain relief from the IEM housing actually looks reasonable sturdy, and has some “give” in it.  The Y-split is rubber, but does include a sliding cinch.  There is no real strain relief at the Y split – but I can’t see this being a problem as they Y split itself is hard but flexible rubber.


Kinky, tangly cable - not my favourite! Plug and Y split


The cable is a 1.2m copper cable in an outer TPC sheath. It feels relatively fragile, and is still displaying kinks from the original folding.  It is also very tangle prone, and is microphonic.  For me it is the weakest part of the overall build of the Twinwoofer, and I hope Tekfusion do review the cable for any future IEMs they develop.  The microphonics from the cable can be negated by wearing over ear (my preferred method), using the cinch, and tucking the cable under clothing.

The 3.5mm plug is a standard 3 pole, straight, gold plated for conductivity, and has strain relief.  The plug itself is very skinny, and you should have no issues plugging this into a full cased smartphone or DAP.


Overall the build quality of the IEM is very good for the price point, but I personally think the cable could be a lot better.




I have one ear canal slightly different to the other one (my right is very slightly smaller) - so I tend to find that usually single silicon flanges don't fit overly well.  However, I initially tried the included large silicone tips, and they fit very well.  They were also reasonably comfortable.  However I switched to a pair of foam tips (very similar in shape to Comply’s Ts-Series tips).  These actually came initially with my Altone200s (but did not work well for me with those IEMs).  With the Twinwoofers they provide a good seal and comfort.  All of the tips I tried gave me reasonably good sonic results with only small changes to the overall sound.  I also tried the Twinwoofers with genuine Comply T400 tips, and the fit and isolation was also very good.


Isolation with the A200 foams or T400 fitted is very good, and I think they’d be good enough for long distance air travel.  Comfort overall is very good – and I have actually slept with these in.  They are relatively flush with my outer ear when worn though, so sleeping can put some slight pressure on the outer ear (YMMV).


There is noticeable driver flex when first inserting the Twinwoofers – but it isn’t an issue after insertion.  This is something that I have noticed from other sealed dynamic drivers in the past – primarily those without a vent or port.


So what does the Tekfusion Twinwoofer sound like, and did they deliver powerful bass with audio accuracy ……… ?




The following is what I hear from the Tekfusion Twinwoofers.  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 X5 as source.


Portable set-up, Twinwoofers + X5 Office set-up, Twinwoofers + Beyerdynamic A200p


Tracks used were across a variety of genres – and can be viewed in this list http://www.head-fi.org/a/brookos-test-tracks.


Thoughts on General Signature


If I was to describe the signature in a sentence – I’d say “very big bass impact, but surprisingly clear (but warm) vocal presence”


I’m finding the Twinwoofers to have a big emphasis on both sub-bass and mid-bass, but the surprising thing so far has been the ‘relative’ clarity of the vocals (especially upper mids).  They are a very warm IEM, and although there is enough detail to allow cymbals to be heard, the emphasis (when bass is present in a track) is firmly at the lower end of the frequency spectrum.


There is a definite V shape here, and I guess Tekfusion are aiming at a distinct segment of the market here (for modern music with bass emphasis), so I can see the reasoning behind the voicing.


Overall Detail / Clarity


For this I always use both Steely Dan’s “Gaucho” and Dire Strait’s “Sultans of Swing” as there is a lot of micro detail in both tracks, and the recording quality for both is excellent.


First playing Dire Straits, and the Twinwoofer’s detail retrieval is what I would term as ‘polite’.  Cymbals are there, but muted.  Mid-range generally is pretty good but tends to get a little smeared by the bass guitar constantly being in focus.  Knopfler’s guitar is nicely represented and actually sounds pretty good.  But I am noticing micro detail that is present on my other IEMs is being hidden by the bass line.


Moving to Gaucho, and the sax intro is pretty good, but again overshadowed by drum and bass guitar.  It’s just not the usual presentation I know from my other IEMs.  Cymbals are once again in the background.  Midrange is again very good – smooth and clear. 


Separation of instruments overall is average, mainly due to some smearing from the bass.


Sound-stage & Imaging


For this I use Amber Rubarth’s binaural recording “Tundra”.  I use this because it’s a pretty simple way to get comparative data on sound-stage.


It’s usually difficult to get a reasonable stage size from an inner ear monitor.  The stage is often quite small / close – with an average impression of space.  The Twinwoofers are a typical IEM in this regard, showing some width and sense of space with this track, but overall imaging and staging is relatively narrow.  Directional cues for everything except the opening notes on violin are good.  Some of the early picking of the violin strings is once again over ridden by the bass.


I also used Loreena McKennitt’s “Dante’s Prayer” and this time the Twinwoofers gave a much improved performance.  There is not a lot of bass line in this track, so all of a sudden clarity overall lifted a notch.  The cello in the background was beautiful, and Loreena’s vocals were up front and clear.  There was no real sense of the space that I know other headphones can exhibit with this track – but I did enjoy the overall balance.  In this track, the applause at the end is so well presented that with some headphones (HD600/T1) I can actually close my eyes and imagine myself in the crowd.  With the Twinwoofers, the clapping does take me into the audience – and there is a sense of space.  But the presentation is very lateral, and not circumaural as I know it can be presented.


Bass Quantity / Quality


Because Tekfusion are marketing these as powerful bass, I need to make sure I focus on this particular section of the review.  The Twinwoofers deliver their promise of powerful bass, and it extends very low as well.  What they’ve delivered is indeed two subwoofers (at times) which are really surprising with the bass impact they can deliver.  When I first listened to the Twinwoofers, I had to play a frequency sweep to see how low these could go, and they had no issues at all in producing copious amounts of sub-bass at just above 20Hz (the limit of my personal hearing starts around 22-23Hz).  If anything (and I know by ear is not accurate), I would estimate that the Twinwoofers actually have more sub-bass than mid-bass – and they have no issues producing mid-bass either!


Listening to Zoe Keating’s “Escape Artist” (Zoe plays Cello – and has a Bandcamp site – definitely worth looking her up!), and the cello is presented really well with great impact and timbre.  I really enjoyed this track on the Twinwoofers.


Then switch it up to something with huge sub-bass impact like Lorde’s “Royals” or Amy Winehouse’s “You Know I’m No Good” and the impact hits the stratosphere.  Especially with Lorde, the bass guitar actually feels like it’s moving air (there is vibration!).  The funny thing here is that Lorde’s voice is still perfectly clear. 


One of the tracks I noticed a real sense of impact with was Mark Lanegan’s “Bleeding Muddy Water”.  Every hit of the drum was like a thud – these deliver serious low bass.


The only criticism I have of the bass is that it sometimes gets so overwhelming that I find I have to lower the volume.  Unfortunately doing this immediately drops the midrange and finer details from the treble.  Bassheads will love the impact – I’m just finding it too much.


Genre Specific Notes


Again for tracks, albums, artists – please refer to this list:  http://www.head-fi.org/a/brookos-test-tracks


Rock – For me, the Twinwoofers perform relatively well with this genre, but for my tastes it is track dependent. Classic rock without a lot of bass emphasis sounds very good – smooth, good bassline, good vocals – fun and punchy.  Hotel California was a great example of this.  Slower rock ballads were also very good with Alter Bridge’s “Broken Wings” and Seether’s “Immortality” both being very enjoyable experiences.  Where the Twinwoofers tended to struggle a little was on faster music like “Diary of Jayne”, where the more complex passage just became a ‘wall of sound’.


Alt Rock – First up was Pink Floyd’s “Money”, and this was very enjoyable on the Twinwoofers providing a really good mix of contrast between the bass guitar and the finer detail of the cymbals, sax and guitar.  Porcupine Tree’s “Trains” is another track that really presents well with the Twinwoofers. The bass is very impactful – but Wilson’s higher voice still comes through clearly.


Jazz / Blues / Bluegrass – Moving to Portico Quartet’s “Ruins” and this track is still very captivating, and smooth – but does not have the crispness of the cymbals that I’m used to. The double bass is pretty good – just a little loose and boomy, but the sax is very good.  Switching to Miles Davis “So What”, and the feeling is similar to what I encountered with Portico Quartet.  It’s a pleasant presentation – but a little muted – not quite as captivating as I’m used to.  Miles trumpet is very smooth, and contrasts nicely with the double bass, but the cymbal work (which is often a highlight of good jazz) is once again muted and distant.


Next up was Blues – so I fired up Joe Bonamassa’s India-Mountain Time, a track that I like immensely.  The Twinwoofers perform really well with this – there is a constant rumble of the bass, but it doesn’t detract from Joe’s vocals or his guitar work. Bass does get slightly boomy at times, and there is not the same clarity I am used to from IEMs like the DN1000 or Altone200 – but that’s hardly a fair comment given the price differential. I still very much enjoyed that different presentation.


Rap / EDM / Pop – Eminem’s “Lose Yourself” is up next, and now the Twinwoofers show their strength.  Marshall’s vocal are still really clear, and the guitar is also very good – and the bass – I’m not usually a fan of this much emphasis but this is perfect for this track. Switching to EDM – and Lindsay Stirling’s “Electric Daisy Violin”once again just slams! Lindsay’s violin is clear, smooth, perhaps not as forward as I am used to – but the contrast is the bass - thumping, but with good definition – the perfect compliment.  I also tried some Little Dragon (Little Man) and some Flashbulb – and it is clear to me, my electronic music does well with the Twinwoofers.  I think it’s the quite V shaped presentation.  The only negative for my preference is the mount of bass with Little Dragon – for me it gets a little fatiguing after a while.  The Flashbulb’s “God is Speaking” is brilliant though – nice contrast, nice bass impact – very enjoyable.


Switching to Norah Jones “Light as a Feather” (a fusion of pop with jazz undertones), and another strength of the Twinwoofers is revealed.  The midrange is ideal for female vocals, and these are smooth, and quite alluring.


Classical / Opera – I didn’t know what to expect with my time so far with the Twinwoofers being a mix of the good and not so good. Netrebko and Garanca's portrayal of Lakme’s Flower Duet was pretty good, just lacking some upper register nuance that I’m used to from my other IEMs.  It is very smooth though, and because these tracks tend to be more bass light, the mid range is allowed to shine (and it does). Kempff’s Moonlight Sonata was really captivating, and delivered a beautiful tonal balance that only slightly darker/warmer IEMs can do with this piece. Switching to Anne Sophie Mutter and Vivaldi’s Four Seasons – and the magic is still there.  The mid range on the Twinwoofers is really quite nice tonally and with orchestral pieces it does deliver.




The Tekfusuin Twinwoofers are very easily powered straight out of virtually any portable device, and I didn’t experience any issues with the 2 DAPs I tested (iPhone 4, or Fiio X5).  Amplification via the A200p did not seem to yield any noticeable benefits.  So these really are smartphone friendly.




I wanted to see if I could lift some of the tracks that I felt suffered with the excess bass, so the track I chose was “The Bad In Each other” off Feist’s album Metals.  Most of the track is pretty good – but when the bass is going strong, it tends to ride roughshod over the lower mids.  So I gave the bass from 30 Hz to 125Hz a 4-5 dB cut (on the X5), and then gradually shelved the mid-bass in steps back to zero.  If definitely helped make the track more enjoyable for me and lessened the fatigue.  I also used the “bass reducer” preset on the iPhone4 and this gave some relief without killing the overall presentation.  So the Twinwoofers do respond well to EQ and you can allow a more detailed overall presentation simply by dialling down some of the prodigious bass that is present.  




I struggled to think of any IEMs that I could compare the Twinwoofers to, as nothing I have at the moment is really as bassy as the Twinwoofers can be.  Then it twigged, and I remembered how bassy the RockJaw Alpha Genus could be with the silver filters.  I used two tracks – Florence + The Machine’s Howl and Pearl Jam’s “Elderly Woman Behind The Counter In A Small Town”.  FOTM’s track has quite an emphasis on bass


Vs Alfa Genus (silver filter) ($85) – “Howl”


Both have very similar sub and mid-bass impact – the Twinwoofers may be going slightky lower in the sub-bass.  But the Twinwoofers are actually a little brighter and more detailed (surprised me).  Alfa Genus sounds a little thicker overall.  With this track and the Alfa using the silver filter, I actually think I prefer the cheaper Twinwoofer.


Vs Alfa Genus (silver filter) ($85) – “Elderly Woman Behind The Counter In A Small Town”


This is not a bassy track, and I chose it more for a contrast, and because I know it extremely well.  The highlights for this track should be Vedder’s vocals, and the contrast between drum, guitars (bass and standard electric), with the cymbals punctuating the overall mix.  Again in this instance, the Alfas have a thicker and slightly darker midrange, and the Twinwoofers are slightly brighter with a  bigger contrast between the cymbals and bass presence.  Overall I prefer the Alfa’s portrayal of Vedder’s vocals but the Twinwoofer’s overall contrast.  Both are enjoyable with this track.




The Tekfusion Twinwoofer appears to be a (mostly) well built budget IEM with a V shaped frequency response.  The main emphasis is on both sub and mid-bass, but they have a surprisingly clear upper mid range and enough lower treble to retain clarity despite the bass sometimes being overpowering. They have great extension at the lower end of the frequency, but do suffer some roll-off and lack of air at higher frequencies.  Mid range is very good – and I suspect that there is a dip in the lower mids in order for the upper mids to shine.


The fit of the Twinwoofers is pretty comfortable, and they offer above average isolation if you get a good seal (tip dependent).


IMO the Twinwoofers are not genre dependent, but rather track dependent – and this comes down to personal preference (for bass quantity) and also speed and complexity of the tracks being played.  They can tend to be boomy with bass heavy music, and can suffer smearing of the lower mid range with very fast paced tracks.


My principle critique of the Twinwoofers would be the quality of the cable which I find sub-par with the overall quality of the product (appears fragile, kinks and tangles).


My litmus question is “would I buy these for myself”, and “would I recommend them to my family”.  For my personal preference (I am not a basshead), my answer would be no – they are simply too V shaped for my personal preferences.  I can see bass lovers enjoying these very much though – especially as the vocals (mid-range) are surprisingly good, and relatively clear.




  • Rethink and redesign the cable for future IEMS
  • Perhaps think about offering a new model with similar midrange, slightly more treble extension, and a little less bass.
  • Consider swapping the current carry case for something a little more practical (cheap fabric zip case would be fine)
  • Keep doing what you’re doing – the voicing on the Twinwoofers may not suit my personal tastes, but I am sure many will find it quite acceptable – especially with more main stream listeners.


Thanks again for the opportunity, and I’ll now see if I can move these onto others in Australasia to sample and review them.



Great stuff dood!!! Pretty much in complete agreement as you can already tell from my impressions posts. ;)
Hello. Thanks for the comprehensive review. Kindly note that the logo is printed on an brushed aluminum plate, and that the plate has a transparent peel-able seal on it for protection against scratches. The transparent seal might have made you think of it as a sticker.
Hi Harry - thanks!  Can I simply remove the cover with no harm then?  it would look a lot better.  I'll amend the review accordingly.
Sure, you can, and it will make the backsides shine even more :)
Great review, thank you 1
Sounds like this bass could blow away my Audio Technica Solid Bass IEMs 
Unfortunately haven't heard the ATs - but yep, the bass is pretty solid and reaches low.    I've just sent the TTs over to Australia today, and H20 will make sure they get into the hands of a few Aussie Head-Fiers - so hopefully might see some comparisons with other gear. 
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