Brainwavz B400 featured

(Video)Brainwavz B400 Quad Driver Earphones Review

Tested at $199

Hi, PAR fam. Today we’re looking at the Brainwavz B400 quad balanced armature earphones. Early in 2017, I tested the single BA driver B100 and B150 earphones and was duly impressed so naturally, I was curious to see what they could do with 4x the driver count.

Needless to say, I wasn’t just surprised by the quality of the sound but found the earphones to have great physical attributes as well. The $150-$200 IEM segment has become a competitive space, so let’s take a closer look at how the Brainwavz B400 fits in.

  • Extremely comfortable
  • Strong noise isolation
  • Good accessory bundle
  • Instrument separation and layering
  • Comes with 2 cables
  • Average bass extension
  • Stock cables are springy

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Brainwavz B400 Specifications
  • Drivers : Quad Balanced Armature
  • Rated Impedance : 30Ω
  • Frequency Range : 10 Hz – 40 kHz
  • Sensitivity : 115dB
  • 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

We were presented with a simple box wrapped in a white cardboard sleeve. The outer sleeve is very simple and just has black text on the front denoting the brand and model.

Beneath the sleeve is a plain, dark grey box with a magnetic front cover. Inside is the standard but excellent Brainwavz zipper case and the B400 earphones. Let’s break down the box contents.

  • MMCX 3.5mm cable with In-Line Microphone and Remote.
  • MMCX 3.5mm Cable
  • Earphone Hard case
  • 6x Sets of Silicone Ear Tips (S M L)
  • Set of Comply™ Foam Tips T-100
  • Shirt Clip
  • Velcro Cable Tie
  • Instruction Manual & Warranty Card (24-month warranty)

As usual, Brainwavz provides a well-rounded bundle that includes everything you need to get started. I was really pleased to find that the largest of the provided eartips actually fit my ears nicely. Although they are the same size as the ones that came with the Brainwavz Koel, the B400 gives me a much more secure and satisfying seal.

Build Quality and Design

The B400 housings are manufactured using a specialized 3D printing process. This allows for more detailed and intricate designs that traditional injection moulding techniques cannot reproduce.

The end result is these fabulous looking, transparent resin shells. They’re also available in several other colours, including ruby, cosmic black, green rage and the new aqua.

You can see the improvements in build quality compared to the earlier B-Series models and it’s clear (pun intended) that Brainwavz production methods have matured considerably since then.

So, the shells are like a crescent moon shape and have Brainwavz branding in the faceplates. You can see the MMCX socket and balanced armature drivers within the housings and I never get tired of gazing into them (when they’re not in my ears)!


The two cables provided are identical except that one has a 3-button remote and microphone and the other does not. A somewhat stiff TPU sheath is wrapped around the internal wires. Unfortunately there is a considerable amount of memory and kinks in the cable that makes them feel less than premium.

Plastic MMCX housings sit at the top end. There is an L and R marking but they are very difficult to find and/or see. Next, a heat shrink shroud forms the pre-formed ear guides.

There is a hardened rubber chin slider which is very secure and works well. The Y-splitter is unobtrusive and has a Brainwavz logo embossed onto one side.

The cable terminates in an angled 3.5 mm plug. Strain reliefs up and down the cable are really good and the cable feels very strong.

Comfort and Noise Isolation

This is hands down one of the most comfortable in-ear monitors I’ve ever used. For my ears the B400 is more comfortable than all of the other Brainwaves BA IEMs, including the Koel. I can wear the B400 all day long with no discomfort whatsoever.

Noise isolation is above average and overall very strong. Little outside noise will reach your ears, especially when you have music playing. Going in the other direction, noise leak is close to non-existent making the B400 suitable for almost any environment you could imagine.

Brainwavz B400 with FiiO M6


Gear used for testing includes the FiiO M6, Sony NW-ZX300 and Soundaware M2Pro DAPs for on the go listening. At home on the desktop, as usual my PC was the source, using MusicBee to feed FLAC files to the FiiO K3 DAC.

It’s an easy IEM to drive and the impedance output of your source is most likely more important than driving power in this case. The B400 was happily driven by all the sources listed above, as well as my Android phone.

The Brainwavz B400 has a balanced and fairly neutral sound with additional warmth. It’s characterized by its fantastic instrument separation, clarity and balance.

Brainwavz B400 frequency graph

For an all BA IEM, the B400 has a pretty impressive bass. Obviously, it doesn’t have the drive or authority of a dynamic driver but that’s part of what makes this bass so good. It has a great amount of texture and great leading edges thanks to its speed and nimbleness.

It’s in the sub-bass that is usually the real challenge for balanced armature drivers and it’s no different with the B400. The sub-bass is very well controlled and has a fast rumble but it doesn’t quite have the reach or extension of a good dynamic driver.

The B400’s mid-bass focus is adequate for my tastes but depending on your music types and personal preferences, it might leave you wanting for some more low end grunt.


The midrange of the B400 is exceptional in its clarity and smoothness. Vocals have good articulation and sound natural. Acoustic guitars and string instruments, like those in “Decades” by Whale Fall, sound fantastic. They sound effortless, rich and smooth.

The Brainwavz B400 is a great earphone for classical music too; songs like Sibelius’ “The Swan of Tuonela” are rendered beautifully with excellent dynamic range and again, that magical layering that this IEM does so well.


Treble notes are crisp and have solidity. There is good detail retrieval and some sparkle with no signs of harshness or stridency. The treble extension is not the best I’ve heard but it is indeed good. It’s light, airy and linear throughout.

The quantity of it is just enough to counterbalance the enhanced mid-bass and maintain an equilibrium in the overall signature without causing any listening fatigue.


In terms of soundstage, the B400 is average in size and slightly wider than it is deep. What stands out here is the stability of the stage and the accomplished layering.

It has a real ‘onion effect’ where different instruments and sounds occupy their own space in the stage; a lot of in-ear monitors just push a solid wall of sound at you. With the B400, it’s almost as if you could reach out and pluck individual sounds out of the air because the positional cues and separation are so on point.


TenHz P4 Pro ($150)

The P4 Pro (review here) has a bigger, bolder sound but isn’t as refined as the B400. Its notes are denser and it has more top end energy which makes the sound more vivid and aggressive.

It has slightly less sub-bass presence than the B400, resulting in the P4 Pro having less warmth. Mid-bass on both IEMs is similar with the P4 Pro having a subtly faster decay.

There is more of an upper midrange and lower treble accent on the P4 Pro, which in addition to the leaner bass makes it brighter overall. Treble is a bit more forward too and I found the P4 Pro to be a little sharper in comparison with the occasional need to drop the volume a bit to avoid harshness.

Where the B400 really flexes its authority is in its separation and layering. While the P4 Pro does have good instrument separation it’s not nearly as masterful and the Brainwavz IEM.

Brainwavz B100 ($59)

The B100 (review here) has a leaner presentation with a more energetic top end. It has less emphasis on the mid-bass and leaner notes from top to bottom. You can clearly detect the lineage that predated the B400 and you can hear how much the sound has evolved and been refined in the quad driver flagship.

Both earphones have a similarly sized soundstage but the B400 has the ability to spread instruments and position them with holographic physicality.

Although the B100 looks very similar physically, the shells are a little thinner and less rounded. The B400 feels more natural in the ears and offers superior comfort during longer wear sessions.

Brainwavz B400 with DAP and a plant with coloured rocks


The Brainwavz B400 was everything I was expecting and more. It boasts extreme comfort, solid build quality and a truly exceptional sound, all together in an affordable and well thought out package.

If you’re looking for an all BA earphone, put this one on your list. In fact, just go ahead and put this one on your list regardless. This one gets a solid recommendation and don’t be surprised if you see it on our Best Universal IEMs list in the near future.

Check out the B400 at Amazon here.

Have you tried an all BA earphone yet? Let us know in the comments below.

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