BTW the human auditory system is a pretty good spectrum analyzer, you cannot get away with
half-baked approaches as spurious signals are very easily detected by the ear even at very low
levels and are often very objectionable. This means paying attention to preventing aliasing and
keeping quantization noise and sampling time jitter under control - certainly for music signals.
[ sorry didn't see the comment at the top of your last reply - so you just want to generate quantization noise by sampling at a low rate, or you want aliasing and quantization? ]