Brainwavz Koel Balanced Armature Earphone Review

Brainwavz Koel feat
Tested at $69

Brainwavz Audio has been at it again and this time they’ve added another model to their balanced armature series. Enter the Brainwavz Koel in-ear monitor utilizing a single Balanced Armature driver.

Brainwavz Audio website:

  • Good carrying case included
  • Excellent build quality and comfort
  • Unique appearance
  • Uncoloured sound
  • Cable has memory and kinks
Tested at $70
Check price on:
  • Driver: Single Balanced Armature
  • Rated Impedance: 30Ω
  • Frequency Range: 16 Hz ~ 22 kHz
  • Sensitivity: 105 dB at 1 mW
  • Cable: Detachable
  • Cable Connector: MMCX
  • Plug: 3.5 mm, gold plated

This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.

Package and Accessories

The Brainwavz Koel comes in a tasteful white cardboard sleeve with the model name printed in bold black letters on the front. Inside the sleeve is the box proper, this time in a dark grey with the Branwavz branding embossed on the front and side.

On the inside cover is the company’s mission statement and to the side is the classic Brainwavz carry case – the same one that the Jive, B100 and B150 models came in. This is a high-quality carry case that is suitable for carrying around and offers a good level of protection to the IEMs inside.

All of the accessories and the headphones are found inside the carrying case. Let’s break down what you get:

  • Brainwavz Koel earphones
  • Semi-rigid carrying case
  • 1 pair of Comply memory foam eartips
  • 6 pairs of silicone eartips
  • Shirt clip
  • User guide

That’s a pretty decent package in terms of contents but I do have some misgivings about it. The Koel has very narrow nozzles so the majority of normal eartips are not compatible with this IEM. For most people, this won’t be a problem but for my ears, the largest tips are not quite large enough. However, fortunately, I have the B100 tips which are just a bit bigger and give me a proper seal.

Even though there are a total of 7 pairs of tips they range from what I would call “extra small” to “medium”. But I know for a fact that I am in a very small minority when it comes to tips and I’m certain everyone else will be fine.

Build Quality and Design

Following a current trend among in-ear monitor manufacturers, the Koel utilizes 3D printed liquid resin housings. This allows more intricate and sophisticated shells than the traditional moulds offer.

Sporting transparent housing with a frosty effect on the surface, the Koel is a unique and very attractive IEM. On the faceplates is the Brainwavz branding plus on the inner side of the shells is an L or R indicating Left and Right sides consecutively.

The single balanced armature driver within does not require any venting so there are no open ports to be found on the earphones. What you will see is an unusual “hump” (for lack of a better term) at the lower front end. This sits in the intertragic notch and gives the monitors a more secure fit in your ears.

Removing the eartips reveals the minuscule nozzles which really are very tiny indeed. There is a ridge on the end that acts to hold the eartips in place and there is what appears to be some type of acoustic filter in the end of the nozzles as well.


The cable is very similar to the one found on the B-Series IEMs from Brainwavz. It feels sturdy enough but it is springy and full of kinks. At the top are the rubberized MMCX connectors followed by pre-formed ear guides.

There is a chin slider/cable cinch present which is always nice to see. Just below that is, of course, the hardened rubber Y-split and finally, the cable terminates in a 45-degree 3.5 mm plug. Strain relief is good from top to bottom and while it’s not the nicest cable, it should be resilient.

Comfort and Noise Isolation

I found the Koel to be very comfortable in my ears. The housings are pretty small and it’s easy to forget that they’re there after a short time.

Noise isolation is pretty average for a small IEM and likewise, the noise leak is very minimal and won’t be a problem in any environment.


Testing was done with the AR-M20 and Shanling M0 DAPs, along with my Windows PC and the FiiO K3 DAC.

The Koel’s single balanced armature driver produces a neutral, uncoloured sound. It has an accurate tonality from top to bottom but does share the typical shortcomings of a single BA monitor i.e. limited end to end extension. At the same time though, it inherits the strong points of balanced armatures as well, such as texture and timbre.


The Koel’s bass is very well-defined and clean. Bass notes have an etched front edge and fast decay with just enough body to maintain some warmth. It’s punchy and light, as well as extremely fast and nimble.

Sub-bass notes are present but don’t produce any deep-seated rumble. If you’re a basshead then this is not the earphone for you. It is instead a very uncoloured and neutral in-ear monitor and this is really reflected in its bass response.


The midrange is an area that single balanced armature monitors often excel at and it’s no different with the Koel. Vocals are liquid smooth but have extremely good articulation. Despite its accurate tonality, the Koel is not overtly analytical sounding.

It works surprisingly well across a wide range of genres and if you want to hear music as it was recorded then here’s your chance. Listening to “700” by 417.3 (yes, that really is a name) the Koel just nails it and is absolutely ideal for listening to this type of music.


The Koel has a crisp and even treble and although it doesn’t have the greatest extension it performs very well for an earphone in this price range. It’s not harsh or fatiguing at all and is loaded with detail and air.


When it comes to the soundstage the Koel has a well-rounded stage with even width and depth. Imaging is quite strong and its ability for layering is impressive for a single BA at this price. Instrument separation is also above average and prevents the sound from being congested.


Brainwavz Koel vs Brainwavz B100 ($59.50 USD)

The B100 (review here) has more of a typical consumer-oriented tuning – an accentuated bass, warmer (coloured) midrange and a rolled off treble. It’s not near as accurate tonally as the Koel but I can see how some people would prefer the B100 as it’s the type of sound signature they’re most likely more used to.

In terms of build quality the Koel is clearly superior but I personally find the B100 to be more comfortable.

Brainwavz Koel vs Brainwavz B150 ($109)

The B150 (review here) is very similar to the B100 but it’s warmer again with a more pronounced but thicker bass and liquid but denser midrange and subdued treble. The Brainwavz Koel has more clarity and better instrument separation and is clearly less coloured than the B150.

Again, I find the B150 more comfortable than the Koel but only by a slight margin. Overall I think they compliment each other well but the Koel, in my opinion, offers better value.

Brainwavz Koel with case


The Brainwavz Koel is a really interesting and accomplished IEM. It’s a bit like a very affordable studio monitor in your ears and in fact, would probably be ideal for mixing or content creation where accuracy and an uncoloured tonality is important.

This would be the perfect earphone for someone looking for a pure but pleasant sound. While there are a lot more sub $100 balanced armature monitors on the market now, very few of them have the refinement of the Koel. Add to that the excellent 24-month warranty and you’ve got yourself a great IEM for the price.

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