Here is a link that will give you some really great info on different diodes. Cody (Self Destroyer) and Jon (Midwayfair) are both members on here and are really smart. Jon's diode listing covers what each diode he reviewed will sound like. Hope this will help you out. But be warned, it could start you on a journey trying to locate some of them, LOL (it did me). Paul who runs DIYGP (link is in header above) has several on the list and he is a really great guy.
http://music.codydeschenes.com/?p=1615
http://music.codydeschenes.com/?p=1615