In my research while making my music I've learned alot of today's live drummers are also triggering sampled sounds at the same time. OR the producer records each drum, cymbal, hihat, snare, bass, etc, as seperate channels and then triggers other sounds and somtimes actually replaces the original recorded drums completely. A common setup for todays music seems to be live drums and a sampled kit played at the same time. I've ALSO read where they will do something like this, record the live drummer, then have 2 slightly different sampled kits trigger the same playing, but pan the sampled kits slightly left and right. The SAME technique used to fatten guitar tracks!! When you say "fatter sound" that doesn't always mean compression was used.