anyone else notice the change of timbre in, say, anthony kiedis when the chili peppers switched from michael beinhorn to rick rubin? listen to anything off of mother's milk and then anything off of blood sugar sex magik and see if you hear it, too. another band i've noticed with is tool. maynard sounds different on aenima with david bottril versus on undertow (don't know that producer off the top of my head). any others?