Sound:
I'm only using low impedance sources and the largest included silicone tips.
Tonality:
The B100 doesn’t differ greatly from the B150 that I will compare it to further below, however they differ a bit in two rather important areas wherefore they don’t sound fully similar.
The B100, roughly speaking, will give you a punchy and tight, kicking upper bass, not that much warmth in the lower midrange that has got just a slight drift to the warmer and darker side, and an overall quite smooth treble that doesn’t smooth out cymbal crashes much but won’t trigger sibilance either.
Compared to a really flat in-ear such as the Etymotic ER-4S, the B100, just as the B150, has got a bit more than 7 dB more bass quantity in my ears with a climax that is mainly located around the upper bass.
Although the bass elevation is mainly found in the lower root and upper bass, it is starting to climb around 650 Hz, reaches its climax around 120, keeps this level down to 80 Hz and then slowly loses quantity towards the sub-bass. It is not a strong roll-off though, so the lower midbass and beginning sub-bass at 40 Hz are still audible with good quantity, however there is not much below 28 Hz anymore.
It is a punchy and kicking upper bass, that, while it won’t satisfy the needs of someone who is looking for a really strong and impactful bottom-end mainly found with most dynamic driver in-ears at this price point, has got quite some impact for a single-BA in-ear and doesn’t sound sterile or boring by any means. The cliché of a thin and bass-light sound from a single-driver Balanced Armature in-ear is definitely not true with the Brainwavz.
The midrange is just slightly on the warmer and darker side and less full compared to the B150’s. I wouldn’t call it coloured, but just say that the upper vocal range takes a step back and therefore darkens this range a bit without making it appear artificial yet.
The middle highs around 5 kHz and the rest until 12 kHz show more presence again, and there even is a moderate elevation I can spot between 12 and 13 kHz when listening to sine sweeps. While cymbals are still a little on the smoother side, which certainly isn’t a bad thing, the elevation in the starting super treble above 12 kHz adds a nice and subtle airiness to the sound.
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When it comes to tuning, I'd always pick the warmer and bassier B100 over the newer KOEL that just lacks bass extension.
Resolution:
Let’s make it short here – the B100 sounds nimble and quick, lightweight and detailed, coherent and well-rendered.
As you might notice, the vast majority of the “Resolution” and “Soundstage” part is identical to what I’ve written in my B150 review, which is mainly because I really think that both are pretty much on the same technical level overall.
The bass, while it is not as tight and fast as with some multi-BA in-ears or the Etymotic ER-4S, definitely doesn’t lack speed and is only very slightly on the softer side and still a good bit better controlled and faster than most dynamic driver in-ears. I also hear it as being a little quicker than the B150’s, which is however not true and just an illusion that is at the latest busted when putting both single-driver in-ears side-by-side, and only appears to be like this because the B100 has got the slightly less emphasised lower vocals.
The midrange has got good speech intelligibility and minute detail retrieval, as it can also be expected from a (single-) BA in-ear.
The treble carries good details and good separation that is not elite-level but good for the price. I don’t really miss much.
The sound is, not really surprising, very coherent, wherefore I would also choose the B100 over the dual-BA Apple in-ears, that, while they definitely show an advantage in the midrange and treble in terms of detail retrieval and are a bit more refined overall, don’t sound as coherent as most single-BA in-ears in the low three-digit/high two-digit price range, including the B100 where everything sounds harmonious.
Being someone who personally prefers in-ears with Balanced Armature drivers over those with dynamic drivers (with just a few exceptions and fields of use), the B100 would also be my personal choice over most similarly priced dynamic driver in-ears because of its higher speed and tightness.
Soundstage:
One will neither get a huge nor a small soundstage with the B100. Who still expects single-BA in-ears to sound congested, which is definitely not the case for a good number of models, will probably be a little surprised that the B100 has got a soundstage that I would say is a little larger than average, with a good width-to-depth-ratio and a good presentation of spatial depth. The positioning of instruments is precise and the separation is good, too, and the presentation also appears quite airy while there is not as much air around single instruments as with most higher-end multi-driver in-ears.
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In Comparison with other Single-BA In-Ears:
MEE audio A151 (2nd generation):
The A151, while it is definitely not among the thin sounding single-BA in-ears and carries some warmth and weight in the lows compared to a really flat monitor, has got ca. 3 dB less bass quantity than the B100, as well as somewhat less quantity in the upper treble. The MEE has got the slightly more forward vocal range.
The MEE has got the minimally tighter and faster bass and sounds ever so slightly more refined in the treble, which I am however only able to make out with very strong concentration on minute details and quick switching between both. The B100 is minimally ahead when it comes to midrange details.
The A151’s soundstage is a bit wider and somewhat better separated.
Brainwavz B150:
To make it short, both sound very similar to me, yet they aren’t identical.
Both have got the same bass quantity while the B100’s upper bass kick is subjectively a bit better distinguishable as it has got slightly less quantity in the lower midrange than the B150 that has got the slightly lusher and warmer vocals in comparison. Both in-ears also sound identical to me in the treble, apart from that the B100 outputs more quantity between 12 and 13 kHz, wherefore it appears airier, less laid-back and more direct in comparison.
In terms of resolution, I definitely see both as being on-par.
Both also sound identical to me when it comes to soundstage dimensions with the B100’s being a little airier which can be mainly addressed to it having more quantity in the starting super treble above 10 kHz.
So my impression is that while the tuning difference isn't significant at all, the B150 is better suited for those who want a somewhat warmer and smoother sound whereas the B100 might be the better choice for those who are looking for comparably less warmth in the lower midrange which makes the upper bass appear to kick a bit more, along with a bit more presence in the upper treble.
Conclusion:
Easily recommended and clearly my choice over their newer, 3D-printed KOEL single-BA in-ear.