Checking out the service notes for a Roland TR-808, it's amazing to see all that goes into making just one sound. Here is a break down of what the Cymbal sound consists of:
six square wave oscillators going through five filters (two band pass and three high pass), three envelop generators and three amplifiers. If you don't believe me, see for yourself:
Ever since acquiring my 808 I've been adding white noise to the cymbal sound to make it sound more synthetic. I thought I was being redundant and that it must already contain some noise, but it turns out that it doesn't and my ears knew what they wanted to hear!