IF there is a significant difference in the quality of sound between one brand of disks in a NAS and another, then something is seriously broken or badly design

IF there is a significant difference in the quality of sound between one brand of disks in a NAS and another, then something is seriously broken or badly designed in the DAC. On the other hand, I don't trust those who don't do controlled experiments to have unbiased conclusions on audio gear. Way back when I cared about audio, I was listening to some high end (~10k/component) cd player + power supply at a Naim dealer. The sales guy was raving about the sound, but it was just wrong to me. The soundstage was just wrong. Weirdly sideways. After a going back and forth a few times, visual inspection proved the speakers were wired out of phase. So, not controlled experiment, and not a magazine columnist doing the miswiring, but if you can't tell when the basics aren't right, how can you expect to hear nth order effects?