More follow-up: with my EMPEG hooked to my home stereo playing the same track as my CD player from the original CD, I noticed a couple things when listening with my good headphones (Grado Labs SR60's) and switching back and forth:

- to match the volume exactly, I had to set the EMPEG to its maximum volume (+10dB "overdrive"). This means that, either my Yamaha CD player is loud or the EMPEG is quiet (or that the MP3 encoding is droppng the signal by 10dB!). While it didn't happen on my test song, on other songs the EMPEG's internal line amp can clearly be heard clipping when set at +10dB volume. I haven't been able to hear any clipping at +0dB volume.

- there are occasional pops and clicks in the MP3, most likely from my cruddy CD-ROM drive (soon to be replaced with a nice Plextor, after which I'll re-rip everything)

- I could distinctly hear the high-frequency cut-off from my MP3 encoder (on this track: lame, v3.70, 128kbit CBR), particularly with wire brushes on drums. I'd never heard this from my computer's sound card, so chalk one up for the EMPEG there.

Otherwise, I didn't hear much in the way of "artifacts" (or at least that I couldn't attribute to the high-frequency cut-off). Once I can get WAV support on my EMPEG, I'll do some more controlled studies. Right now, I'm not really comparing apples-to-apples and I'm not doing a double-blind study, either.

Stupid feature request that will never see the light of day: say I've got a playlist of tracks that I know are all the "same" song but encoded differently. It would be great to treat them as if they were the same song and let me play them all "simultaneously" (e.g., seamlessly flip from one encoding to the same offset in another). Given that they're all different bitrates (and CBR vs. VBR), this feature would be a pain in the rump to actually implement, and would never match up quite perfectly. However, given the EMPEG designers' propensity for geeky features, you never know what's going into production next.