Brainwavz KOEL: You’d be cuckoo not to enjoy this!


Today we’re checking out the new single armature earphone from Brainwavz, the KOEL.

At the beginning of 2017, Brainwavz decided to revisit balanced armatures with their new B-Series earphones. The single driver B100 was my favourite of the the two I had heard at the time (B100 and B150), completely winning me over with a crisp, detailed signature that didn’t skimp on the low end extension. Add to that a hilariously low price, a tiny, low profile housing, and the best preformed ear guides on the market. The B100 was nothing but win.

Like the B100, the KOEL features a single balanced armature as it’s driving force. Taking queues from the B200 and B400, the housing is 3D printed using a high quality liquid resin, though with a much more unique shape this time around. MMCX replaces the fixed cable system of the older B-Series models giving users the ability to swap to a different cable should they so choose.

Is the KOEL worthy of being the only single BA model in Brainwavz’s current lineup now that the B100 and B150 are no longer available? Let’s find out.


A thank you to Marlon with Brainwavz for sending over a sample of the KOEL for review. The thoughts within this review are my own opinions and do not represent Brainwavz or any other entity. At the time of writing, the KOEL was retailing for 69.50 USD. You can check it out here:


The KOEL is surprisingly lax when it comes to pairing it with various sources, so, I just picked my favorites and went from there. It spent most of it’s time with the Shanling M0 or Radsone Earstudio ES100 paired via Bluetooth to my LG G6, LDAC codec engaged. It spent less time with the ES100 acting as an external amp for my Asus FX53V laptop.

Personal Preferences:

I listen primarily to various EDM sub-genres (liquid drum and bass, breakbeat, drumstep, etc.), hip hop, and classic rock. My preferences for earphone tuning are quite relaxed and as such their is no one signature I look for. The HiFiMAN RE800, Brainwavz B400, and Massdrop x MeeAudio Planamic are examples of earphones with wildly varied signatures that are enjoyable for different reasons. I generally listen at very low volumes, so keep this in mind when perusing my thoughts on how an earphone sounds.


  • Driver: Single balanced armature
  • Impedance: 30ohms
  • Sensitivity: 105db @ 1mW
  • Frequency Range: 16Hz – 22kHz

Packaging and Accessories:

I really like the packaging Brainwavz has created for their armature series. It has a very premium feel to it compared to much of the competition. A big part of this is because it shares a number of qualities with the packaging of the significantly more expensive HEM series of earphones from Optoma Nuforce.

On the front of the cream white exterior sheath in a clean, contrasting black font. you find the usual Brainwavz branding and model information. In addition, there are notifications for the inclusion of Compy foam tips and Brainwavz’s generous 24 month warranty. The sides of the sheath are completely blank while the back contains some trademark info, the Brainwavz logo, and a number of images to coincide with the contents.

Sliding off the sheath reveals a matte grey box with ‘Brainwavz’ pressed into the magnetically seal flap and ’24 month warranty’ pressed into the main panel. Flipping back the flap you find the inner left panels contain the Brainwavz mission statement and a short description of what the warranty covers. In the enclosure on the right you find one of Brainwavz’s outstanding black and red elongated hard shell cases set within a foam insert. Resting on top of the foam, surrounding the case, is a paper insert with a psychedelic colour scheme thanking you for your purchase. Within the case resides the KOEL and accessories. In all you get:

  • KOEL earphones
  • MMCX 3.5mm cable
  • Shirt clip
  • Velcro cable tie
  • Comply T-100 foam tips (m)
  • Single flange silicone tips (s/m/l x2)
  • Manual and 24 month warranty card

Overall a great accessory kit. You get one of the best cases in the business, quality ear tips, and some potentially useful little extras like the shirt clip and velcro strap. No complaints here. Plus, you can’t argue with a 24 month warranty which shows that Brainwavz is confident in the quality of their products.

Build, Comfort, and Isolation:

Like it’s bigger brothers the B200 and B400, the KOEL features 3D printed resin housings with a low profile, over ear design. A unique aspect of this jellybean like design is a small protrusion out the base of each ear piece that nestles down into the tragus and antitragus of your outer ear, essentially serving to lock the KOEL in place. I found this design to work quite well and was able to wear it comfortably for a few hours at a time. Those with smaller ears might experience hot spots, but we shall see once they get into more hands.

The construction itself is quite nice. Unlike my early B400, the KOEL’s frosty shells are smoothed and polished on the exterior. There are no sharp edges or misaligned parts. Neatly integrated into the spine of each ear piece rests an MMCX port. It protrudes ever so slightly which should allow you to fit a wide variety of after market cables should you be keen on swapping out the included one. The Brainwavz logo is printed into the inside of the main face of the body, with L/R labels printed on the inner face next to a tiny vent. Not only is this functional and pretty cool looking, but it completely negates problems like labels rubbing off, something that is usually an issue on earphones where that info is painted on. The nozzle is smaller than average as is usually the case with armature based earphones. At around 4mm wide with a small ring to hold the tips on, you’re not going to be able to swap to something like JVC Spiral Dot tips without making an adapter. The KOEL has a small Knowles-style filter fitted into the tip of the nozzle which is great for not only protecting the driver inside, but also for easy cleaning should you get dirt or wax on it.

The cable will be familiar to fans of the brand. It features multiple twisted strands coated by a tough, matte black sheath. While it does tend to retain bends out of the box and is a bit springy, this cable has shown me time and again that it is tough as nails. Plus, microphonics are pretty minimal, strain relief is prominent, and you get the same style of angled ear guides that were first introduced with the B100 and B150. I love the shape of these guides as they work very, very well. In fact, I do my best to mimic it as closely as possible on earphones with memory wire that actually works. The MMCX plugs on this cable are great too. While the cable can spin in place, which I know some of you out there dislike, the connection is strong enough to prevent that from happening during regular use. I’m sure as the product ages and after numerous disconnects it will loosen up, but out of the box the plugs are nice and tight, but not so tight they’re difficult to detach.

Isolation surprised me at how good it was. Given the fairly shallow insertion depth and vent, I was expecting isolation to be pretty average but it’s not. Typing on my laptop without any music playing, you can just barely hear key strokes. Once you’ve got music going, they are completely gone. When taking my nightly walk through the city, I was forced to leave one ear free so I could hear traffic. Tossing on the included Comply tips just ups the isolation to even more impressive levels.


The KOEL has a well-rounded signature for a single, full-range armature. It’s not too dark, nor too bright, nor too mid-centric, instead finding itself playing a quality balancing act.

Treble is clean and tight with excellent control and good extension. I didn’t notice any of the early roll off common to the driver format. Emphasis resides mainly in the lower treble helping with clarity and resolution but limiting sparkle and shimmer on cymbals and chimes, as noticed on “Pure Narcotic” by Porcupine Tree. I tend to prefer this over upper treble emphasis as it generally proves less harsh and fatiguing over longer listening sessions.

The KOEL’s mid-range is refreshingly neutral to my ears, sitting in perfect harmony with the rest of the signature. Male vocals are dense and textured without coming across veiled or smoothed over. Aesop Rock’s “Blood Sandwich” shows off the KOEL’s mastery of sibilance, and that it can hush the discomfort such a quality can cause. The female vocalist on Massive Attack’s “Teardrop” sounds sweet and innocent and it captures the slight breathiness of her performance perfectly. The piano chords that dot the background sound powerful enough and accurate, with plenty of texture to match. This is an amazing mid-range in my opinion.

While I certainly wouldn’t say the KOEL stumbles in the low end, it is the weakest part of the presentation. Going back to “Teardrop”, the trademark deep bass note that opens the track is just barely reproduced. The KOEL’s low end is more suited to something like “Crime of the Century” by Supertramp where the drum slaps that kick in around 2:21 have impact and presence, and the low, low note entering at 2:44 has a satisfying reverb to it. These aren’t basshead earphones, that’s for sure. If you are more keen on texture and speed and don’t listen to music that requires deep bass, you’ll likely be quite pleased.

Imaging and sound stage are quite good for a single armature. In the closing moments of Aesop Rock’s “Kirby”, he repeats advice from his therapist; “I don’t know, maybe get a kitten”. The statement clearly and smoothly shifts just off centre left and into the distance, then does the same in the right channel, repeats the cycle once more, then meets in the middle and fades forward as the song closes out. The KOEL handles this movement very well. Layering and separation are rock solid too with the KOEL able to make heads and tails of the confusion that is the last few minutes of improvised jazz on King Crimson’s “Starless and Bible Black”.

Select Comparisons (volumes matched with Dayton iMM-6):

Brainwavz B100/B150 (discontinued): The KOEL’s bass doesn’t extend quite as well as the B100 and instead falls right in line with the B150. Focus is on the mid and upper-bass with little in the way of sub-bass presence. The B100’s treble is more prominent with additional upper treble that gives it a bit more sparkle than the KOEL. Again, the KOEL’s treble emphasis is right in line with the B150, though with the clarity of the B100. The KOEL’s mid-range shares a warm, lush presentation with the B150, but with the detail of the B100, and sets the listener further back from the action than either of the B models. We’ve got a ‘sitting in Row 1 versus Row 4’ kinda thing going one. Sound stage on the KOEL bests both older B models, though I hear the the KOEL and B100 going head-to-head in terms of imaging accuracy, layering, and separation. Overall the KOEL sounds like it takes the best of the B100 and B150, then merges it into one product. The only thing I end up missing after going back and forth between them is the B100’s low end extension.

I was lucky to be one of the first to review the B100, and as such my review sample is a unique, pre-production model with 3D printed shells. While the basic design was final, it was certainly a little rough around the edges. My B150 was a product model and looked the part with it’s glossy, piano black finish, a higher quality fixed cable that is actually the same as the one on the KOEL, and improved fit of the constituent parts. Still, comparing the B100 to the KOEL is neat since you can see how Brainwavz improved and refined their printing process, enough to go from using it only for prototypes to making retail ready products.

That said, I do think the build of the older B-Series models is nicer overall since they were made using more traditional techniques. But, that also comes with limitations. If there is a design flaw to be addressed or an improvement Brainwavz wants to roll in, applying it is more of an ordeal. By printing their own shells, Brainwavz can easily make mid-production improvements to the product. The B400 is a prime example of this. The nozzle on the original version was long and slim, just like on the B150, but brittle. It was later updated to be thicker and more robust, something that would have been much tougher to address with the B100 and B150.

EarNiNE EN120 (79.00 USD): The KOEL comes across smoother and more laid back than the EN120 with a less vibrant, more neutral-leaning signature. The EN120 has more vibrant, detailed treble with a mid-range that is physically set more forward within the sound stage. The EN120’s mids do less to reduce sibilance and can get a bit sizzly where the KOEL remains calm. However, they do display that somewhat breathy, almost raspy presentation shared by other earphones in the EarNiNE lineup that is unique to their in-house designed armatures. I really quite like that quality since it gives the EN120 a distinctive character. Bass on the EN120 seems to dip off a little later and has more mid-bass punch and slightly more texture. Sound stage on the KOEL is much larger with similar imaging performance. Layering and separation on the KOEL are superior. While I love the distinctive qualities of EarNiNE’s custom armatures, the EN120 doesn’t display the same level of refinement in it’s signature and I’d rather step up to the KOEL.

The EN120’s stainless steel, barrel-shaped housings feel more premium and feature flawless fit and finish. It has a light, flexible braided cable that is outstanding in my experience, but is also fixed to the housing. That’ll be a deal-breaker for some. Comfort is pretty even in my ears, but the EN120’s traditional shape is small and more flexible since it permits cable up or down wear.

FiiO FA1 (99.00 USD): The FA1 and KOEL are both 3D printed earphones with single armatures and MMCX equipped removable cables, though the FA1 comes in a full 30 USD more expensive. The FA1 is slightly more treble forward with additional energy in the upper treble regions. While not quite as refined, the FA1’s treble gives chimes and cymbals more sheen and in general sounds more exciting. The KOEL’s mid-range isn’t as forward, either in emphasis or stage placement, but it is warmer, fuller in body, smoother, more natural, and just as detailed and crisp. Bass on the FA1 sees a slight bump in emphasis and extension to a slightly greater depth, though it still doesn’t rumble like something with a dedicate low-range armature, such as the KZ BA10. KOEL still has an edge in impact and texture. Raw sound stage size goes to the KOEL as it is able to toss effects further into the distance, however, the FA1 is able to bring sounds in closer and as such is the better performer with intimate vocals. Imaging, layering and separation are pretty much on par. Overall, I think the KOEL is more enjoyable and a slightly better performer.

In terms of build, it’s clear the FA1’s extra 30 USD can be found there. As much as I like Brainwavz’s improvements to their 3D printing process, and appreciate the unique and comfortable designs they have come up with, there is a rawness to their shells and over construction not present in the FA1. The fairly common (see Kinera H3 and Idun, Tenhz P4 Pro, and TRN IM1 for an idea of the FA1’s shape), custom-like housings seem to be crafted with a more matured process, from the smoother surfaces, to the more well-defined nozzle, to the stylish face plate. The FA1 also has a more impressive cable given it is VERY similar in look and feel to what Campfire Audio included with the Polaris. The FA1 has a premium air to it that the KOEL just can’t match.

Final Thoughts:

At the start of this review I asked if the KOEL was worthy of carrying the mantle of the only single-armature model in Brainwavz’s lineup. I think the answer is yes. The new housing design looks nice and feels great to wear. The addition of removable cables is a huge plus that many wanted from the B100 and B150. Add to that a sound signature that pulls from earlier models to create a veritable “best of” that is more versatile than either the B100 or B150 were as solo products, and you’ve got yourself a quality earphone. The only thing I’m missing from the KOEL is the B100’s sub-bass, but I’m happy to waive that for the amazing mid-range performance few earphones in this price range can match.

If you’re in the market for a new armature-based daily driver, you can’t go wrong in giving the KOEL a shot. It’s a fantastic new addition to Brainwavz’s balanced armature lineup and a worthy replacement for the B100 and B150.

Thanks for reading!

– B9Scrambler

***** ***** ***** ***** *****

Some Test Tunes:

Aesop Rock – The Impossible Kid (Album)

Hail Mary Mallon – Are You Going to Eat That? (Album)

King Crimson – Lark’s Tongues in Aspic (Album)

King Crimson – Starless and Bible Black (Track)

Supertramp – Crime of the Century (Album)

Infected Mushroom – Legend of the Black Shawarma (Album)

Gorillaz – Plastic Beach (Album)

Massive Attack – Mezzanine (Album)

Fleetwood Mac – Rumors (Album)

Run the Jewels – Run the Jewels (Album)

The Prodigy – The Day is My Enemy (Album)

Tobacco – F****d Up Friends (Album)

Felt – Felt 2 (A Tribute to Lisa Bonet) (Album)

Michael Jackson – Thriller (Album)

The Crystal Method – Grace (feat. LeAnn Rimes) (Track)

Jidenna – Long Live the Chief (Track)

Skrillex – Ragga Bomb (Track)

Big Grams – Run for Your Life (Track)

Funkadelic – Maggot Brain (Track)

Aesop Rock – Fishtales (Track)

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