I need to discern if the headphone section and dac are the reasons for good audio. Please try other headphones with the 10 and please try those hi rez earphones on another smartphone (6s plus or whatever besides the s7e).
Ok .. so i tested the HTC Hi-Res buds and a pair of Xaomi Piston 3 earbuds in an
iPhone 6S+, S7e & HTC 10.
The Hi-Res audio buds do sound better in ALL devices compared to the Xaiomi Piston 3.
The HTC 10 has been calibrated with it's adaptive hearing feature that tailors 'all' audio headphones to your hearing.
The S7e had adapt sound enabled and corrected to my own hearing.
The 6S+ is just on sound equaliser, that is all.
The HTC 10 with boom sound adaption turned on makes audio in both headphones sound great - though the hi-res audio buds are better.
With boom sound turned off the HTC still offers a clean sound, but sounds pretty much identical to the 6S+ and the S7e (with adapt sound turned off).
The S7e with adapt sound turned on, and hi-res converter on - the Hi-Res audio buds from the 10 sound fantastic too. However the volume level is still very much less than the 10.
The S7e with adapt sound turned off, sounds much the same as the 6S+ & HTC 10 (with boom sound off)
The 6S+ sounds better with the hi-res audio buds than the xaiomi - but still not as crisp as either the S7e or HTC 10 with their audio modes enabled.
Essentially the 10 has more power to drive volume (more powerful amp) regardless, but with standard headphones other than volume - it sounds much same as S7e when you have calibrated that with adapt sound.
Hope that makes sense.