Untreated CDs in untweaked systems are kind of the worst case scenario, inasmuch as they almost ALWAYS sound thin, wiry, bass shy, rolled off, tinny, electronic, lumpy, two dimensional, boring, synthetic, fake, congealed, and a lot like paper mache.
This is why I don't listen to CD's. I listen to .wav rips of CD's. The operative word is "almost". There are very good digital systems now that beat even the best vinyl and sound very much analog. I'm lucky enough to enjoy one of these. It's much more difficult to make digital sound like analog than making analog sound like analog.
Steve N.
Empirical Audio