This and That:
Comes with the typical Brainwavz storage/carrying case that was used at that time (it's smaller than the newer ones, however similarly designed).
Unique design, good build quality.
Cable not that supple but springy. Strain relief not sufficient either. No chin-slider.
Sound:
Low impedance sources, largest included single-flange silicone tips.
Tonality:
The sound signature could be described as mostly balanced to rather neutral, although it is ultimately a bit more on the w-shaped side.
Depending on if the inner vent is mostly blocked or not, which might depend on one's individually different ear geometry and fit, the bass will be either rolled-off (open vent) or mostly flat with a moderate lift that is only in the true sub-bass and lower midbass. That said, it would've been better if that inner went weren't there in the first place, so that the lows were perfect for everyone.
When it comes to bass linearity and extension for everyone, my HiFiman RE400i and Fostex TE-02 are better.
The mids are somewhat elevated, creating a more intimate presentation of voices. The vocal timbre is pretty realistic with just a little darkness.
The middle and lower highs are relaxed in the background, while there is a mild peak around 8 kHz that saves the highs from sounding too dark. As the middle highs are in the background and as it's just a very mild elevation, there's no harshness or sharpness.
There's another peak around 13 kHz, but it's not really in a relevant area anymore anyway. Extension past that is excellent.
Resolution:
The resolution is adequate for the price range below $100. Overall the M3 doesn't sound as clean, tight, fast and precise as my Fostex TE-02 or Logitech/Ultimate Ears UE600vi (or the Brainwavz B100), however surpasses my Brainwavz R3, and also slightly my HiFiman RE400i.
Midrange resolution and speech intelligibility are especially good, with detailed highs as well, although the high note separation isn't as good as that of more expensive in-ears. The lows don't sound slow though.
The bass is mostly detailed and reasonably controlled, however somewhat on the softer side and also softens a little towards the sub-bass. It's what I would call a pretty typical dynamic driver bass quality presentation.
Compared to my Sennheiser IE 80, the M3 sounds tighter and faster in the lows.
Soundstage:
Expansion to the sides is about average and not as wide as that of the Brainwavz Jive, R1 or Sennheiser IE 80.
On the other hand, the imaginary stage sounds deep and also authentic when it comes to layering.
Instrument separation and imaging are quite precise for a dynamic driver in this price range, surpassing the R1's and IE 80's placement precision by appearing somewhat less foggy, however without reaching the precision of the UE600vi or TE-02.
Conclusion:
In terms of tuning, the M3 is Brainwavz' most neutral, best dynamic driver model with a matching technical performance for a dynamic driver in-ear in this price range.