Well if we got rid of all reviewer bias and did level-matched blind listening tests of all modern DAPs, all DAPs from $50 to $50000 may* sound exactly the same, modulo differences in output impedance and optional DSPs, so I find your desired emphasis on sound quality a bit ironic! We do know for example that while measurement results vary, the magnitude of the differences between the best and the worst out there, when compared against established thresholds of audibility, goes against the common assumption that every DAP must sound any different, let alone wildly different as commonly assumed. Of course, we still strive after the best result on paper, and do exhaustive listening tests to make sure that nothing unexpected goes astray despite picture perfect results on paper (even to the point of hand-picking boutique components to produce perceived sonic changes--fine by me, as long as it doesn't damage measured quality), but to then see our work then go into a bit of a lottery in sound comparisons from reviewers pains me a bit, and allegations that those aren't given enough weight pains me a bit more. Of course, blind tests of the scale and diligence required to establish the facts for players currently on the market won't ever come by, and even if it did, would become out of date the next time a player comes out, so we'll never know for sure.
*Emphasis on MAY
The crux of the matter, if you ask me, is that improvements on DAP quality improves the PRECISION with which the input signal is reproduced at the earphones, but does nothing for ACCURACY, when the inherent distortions of a headphone system are accounted for. IEMs almost always resonate with your ears creating sharp resonance peaks in the treble (although I hear the Seeds II will have something to combat that), and all headphones as a matter of course gives not "soundstage" but only "headstage", a stage of sounds inside your head confined by the way they go on / into your ear. Even recordings themselves may have issues such as boomy bass or overenthusiastic sibilance that were overlooked at the time of pressing. None of this is corrected for when you do the audiophile thing and try your hardest to keep the signal 100% bitperfect digitally and unchanged in the DAC. It's like buying an atomic clock which does not miss a second in a century only to set it to the wrong time zone.
I don't know if DAPs really sound exactly the same as each other, but being used to the drastic improvements from using tools even more advanced than MSEB in tailoring earphone response and music quality to my ears and then correcting the in-head phenomenon with further signal processing, I can't really be made to bother about differences in sound between DAPs in which none of such improvements are available--unlike HiBy DAPs, where we start off with MSEB and we at EFOtech hope to bring the advanced improvement technologies I'm hearing out to the general public in the future as well in collaboration with HiBy.
Besides, I care more when people can't listen to the music they want, at all, or not as easily as they want the way they want it, owing to software issues. When something like that happens, be it incompatibility with a certain streaming provider, or malfunctions / idiosyncracies in an advertised navigation / output feature, I report straight away. I hope to see our DAPs become the most accessible gateway to all the different music sources out there in this new connected world. And sound the best at it, not just by having the best audio "precision" but also the best "accuracy", via what is mentioned above.
Please note, I will not answer any follow-up questions to this post, as this is obviously a very touchy subject, for me being who I am, and for this part of the forum.
