The Yinyoo IN8 is a nice pair when it comes to bass. Their mids, however, are not what I would expect from hybrid earphones, and their highs are rather disappointing and unnatural. For these earphones' price, I expected some higher level of audio transparancy and definition, but what I got was more like a louder and upfront version of YINJW P8.
The IN8 come with the cheapest, most generic translucent white ear tips that is possible to get. The pre-applied M sized tips are so thin and soft that I found them to be quite useless when it comes to getting a seal. The L size tips are narrow-bore, but they did the job. Overall, the earphones are light but quite long, which means they stick out a lot and there's nothing besides the tips that's keeping them inside your ears.
Lows / Bass
The bass sound quite nice and warm. The lows are mainly focused on the mid-bass, rather than the sub-bass, which inflates the sound a bit. However, the bass gives enough warmth and impact to every music genre, even the most bassy ones, without overpowering the mids.
Mids / Vocals
The mids sound overemphasiszed and a bit harsh, especially noticeable when listening for more than just a while on above-the-average volume. With that, not much impressive detail to be expected as a result of lackluster and discolored treble. The soundstage seems to be narrower than usual, probably because of the very upfront vocals and mid-based instruments. Vocals and instruments sound a bit metallic and darkish. Guitars sound smoothened/blurry and veiled.
Highs / Treble
The weirdness of IN8 begins in the treble. The upper-mids and lower-highs are very emphasized and even somewhat harsh. The timbre is just not right - it's a bit dark and noticeably lacks brilliance and subtle detail. The best subject for comparison are Tennmak Pro and URBANFUN Hi-Fi MARK II (Beryllium). While these two keep a balanced and natural experience for the mids and treble, the IN8 just don't have that shine and sparkle in its treble and the detail isn't that impressive.