Since I am finally home, and the late nature (or pathologically early, I guess) nature of my arrival meant I had already slept too long to do so when I got home, I got to spend a few hours playing with Amazon HD Music.
Very mixed bag so far.
The app is largely horrible, at least on Mac OS. It’ll only output to the default audio device (same braindead behavior that Spotify exhibits and they have persistently not bothered to fix for YEARS), and it does not automatically switch the bit-depth or sample rate on the output.
That wouldn’t be a big deal, but I’ve run across a number of “HD” (or “Ultra HD”) albums for which various tracks are at different bit-depths and rates. Which means if you manually set the output rate (via Audio MIDI Control) to, say, 16/44.1 … you wind up with everything else being forcibly resampled in Core Audio.
Also, no option for Direct or Exclusive output which is, I suspect, the reason that most of the stuff I’ve compared has sounded better from TIDAL or Qobuz (in no case, so far, has Amazon HD sounded better) either via their direct apps, Audirvana or Roon.
The app is worse than TIDAL and Qobuz (for reference, I think the Spotify app is pretty bloody awful too … it’s just differently-shitty than the TIDAL and Qobuz ones).
Didn’t find any of the oddball tracks that I can’t get in TIDAL or Qobuz on Amazon either (they’re not on iTunes or Spotify either).
If they fix the app so it reliably offers bit-perfect output on Mac OS (i.e. automatic sample rate/bit-depth switching) and allow for Direct/Exclusive output, I’ll probably keep it around. For it to get much use for critical listening, however, it’s going to have to get integrated with Roon and/or Audirvana.
At least it’s another option, but it’s an inconvenient one at present with no quality-benefit over the existing services I use at present.