The source disc can determine the distortion when it has identical tracks with different amounts of distortion added in during the mastering process. The tracks are specifically designed to show different pschoacoustic phenominom. If you haven't seen 'My Disc' I highly suggest you pick up a copy. The liner notes alone are worth the cost of the disc.

 

The Autosound 2000 CD's are very cool as well, I believe one of them is the re-labeled "my disk". I was very suprised how hard it was to hear 1%-5% distrotion even with pure tones, much harder with music.