Performance

The S5 is definitely a step up from the S1 in construction and sound quality. The first thing you notice straight out of the box is that midrange clarity is really good, on par with a set of HiFiMAN in-ears, but without being overly analytical. The driver is fast, behaves well, and has obviously been trimmed around good bass performance by MP4Nation. It is clear that the Brainwavz in-ears are tuned for midrange and bass performance rather than optimum treble. This does not mean that the treble is bad; in fact, it is quite good for a set of $100 in-ears, but it is not on the same level as with the HiFiMAN RE-400s, which cost about as much. The extension and detail seems a little weaker on the S5s, but run the RE-400s and S5s on a normal source and the difference is negligible.

Overall, the S5s are very pleasant to listen to for even longer periods at a time. The upper midrange is pretty much sibilance free, and there are no annoying oddities. The decay is good, but perhaps a little exacerbated with some types of music. Compared to the HiFiMAN in-ears, this gives the S5s a slightly hollower sound, which is perfectly fine, though perhaps not completely accurate to the source.

The bass is one of the S5's stand-out features. It is full, quite tight, and has a real "slamming" sensation to it. Their low-end is close to perfect as it is fast enough to handle complex passages without messing up the midrange. Extension-wise, these are right up there with the RE-600s and Westone 4Rs, which means they go really low. The bass is also prominent, but not absurd.

Noise attenuation on these is on par with all the other dynamic driver in-ears I have heard over the past couple years.