Ah yeah, good idea. I can try that.

Before I do that, though, it'd be nice if I could find the command line option in Sox to increase the quality of the MP3 encoding when it re-encodes. Some of the artifacts that come up at its default crappy 128kbps encoding are similar to bad resampling noise, and so I have to listen closely to be able to tell the difference. I can't find it in their dox.

And their dox on the resampling options (rate -q|-l|-m|-h|-v) are super-unclear as to which ones get you the highest quality.

And finally the dash character they show in front of parameters in the doc file isn't a hyphen (even though it's a hyphen in real life), it's some other hyphen-like character (−), so when I search the docs for "-q" for example, it doesn't find any the instances of the q parameter in the docs, even when I'm staring right at one right there. Boy that's annoying.

Anyway, if you can tell from that thing how to control the MP3 encoding quality, let me know.

In the end, I think I've already got the answer to my first question: "- Is it true that the Empeg won't play 48khz MP3 files well, resulting in distorted playback?" - The answer is TRUE.

Now I am still wondering about the other questions:
- Is it true that the issue is that the DAC is a CD-player DAC which can only accept 44.1khz properly?
- Does anyone know of any other hardware-based MP3 players that will have the same problem?
- Can anyone think of other situations where a 48khz MP3 file will play back poorly on other kinds of equipment?