if an audio CD were burned using mp3s or wavs?

Check if there's a frequency cut-off. Lossy codecs never encode the whole frequency range.

if you don't be able to hear the difference you could rip one track from the cd to wav and load it in a wave editor like soundforge (win) or audacity (linux). you can create a spectrogram and if there is is lowpass in high frequencies it was burned based on lossy encodet tracks.

BadHorsie

damn! ...one minute to late

BadHorsie

mp3pro does, at low bitrate... but it's not difficult to guess the encoding process
mpc --insane with old mppenc.exe version (< 1.02)
vorbis
aac PSYTEL -archive and -ultra

Blade too.

I stand corrected. B)

EDIT: But anyways, it's still a good way the check if the cd was burned from *mp3s*.