UiiSii US90 probably has the same drivers that the HM6 and HM7 have, and even the build quality, nozzle diameter and tips are the same as HM7. The sound signature is basically the same, but the mid-bass is more boosted and the clarity in the mids and highs are not as good, for some reason.
If you're planning to buy these, I'd recommend going for the HM7 instead - they look more serious and sound a bit better.
Soft paperboard + soft plastic (clear)
M, white (translucent), ø6mm grey bores
S+L, white (translucent), ø6mm bores
Metal, ø6mm nozzles (ø5mm bores), soft strain reliefs
Plastic (matte), single-button
Metal, no strain reliefs
Silicone (rugged), 130cm, soft, straight
Metal, straight, short, soft strain relief
The earphones are tiny, light and comfortable. They have an orb-like shape, and fit in a very specific way into your ears and stay there firmly.
These earphones don't have extraordinary sub-bass. There's quite a noticeable mid-bass boost, that is more noticeable on US90 than it is on HM7, which adds some muddiness to the sound.
Very clear and vivid vocals, and also pretty loud. There's some clarity degradation compared to HM7 and vocals sound a bit more fat.
The treble is quite excellent for such cheap earphones, yet a bit worse on the clarity department compared to HM7. Overall, the highs are bright a crisp, but just a bit dirty.
