Cons: Soundstage is too small, Mids are muffled, Powerful deep bass but squeezed in small acoustic, Treble is not seperated enough, Overall detailless sound
after M4 & Xiaomi Piston 2 (they were similar), i finally got a M5 to audition. i listened it for 2 days and here's my thoughts: soundstage is the same again, small in every aspect. bass, treble, vocals, mids everything placed just near another and the bass is too deep & powerful for this kind of soundstage. when you open up the bass, the result is going just worse for everything else. no detail in songs, everything sounds muffled. just like on the M4 & Piston, this is also a very bad earphone.
no need to analyse everything seperately. just switch to better models with wide soundstage, you'll instantly hear more detail both on the treble, mids & bass. narrow soundstage causes everything to drop detail. comparing the M4-M5 to each other, i think M5's 30hz deep bass response is better (and lacks some punch unfortunately due to congested soundstage again, it's something like that: body and the punch are exist together in the exact same space and lowers the overall bass quality/feeling) but months passed after i used M4, so i cannot make a 100% conclusion about this comparison right now but i'm 90% sure about m5's bass is much powerful. and i feel no need to conclude about this because i'm sure from their overall potential so i'm not planning to buy them again just to conclude about bass power.
so just don't buy & don't listen to anyone who says they're good for anything. stay away from M4-M5 & Piston. they're the most basics out there.