I just did some tests to evaluate the speed accuracy of the playback drives
around here.

Playing a wav file on a computer uses the computer's clock but playing an
audio disk on a computer drive or standalone/offline player uses the
drive's own clock.

Plextor 48/24/48a... 0.0004 % error
Plextor 40Max... 0.2 % error (shameful)
Denon standalone... 0.01% error
Panasonic Walkman... 0.24% error
....

(The low error on the first Plextor makes me suspicious that it somehow
used the computer's clock.)

I had hoped for better. Oh well.