I had the same problem with my 22s. ry to isolate what speaker & what driver the buzz comes from, then remove that driver. I'm willing to bet you that you've got a wire that's touching the driver basket and is vibrating at low frequencies. That's what was wrong with mine.

Pioneer VSX1014-TX HK DVD31 M22ti mains VP100 center M2i surrounds SVS PB10-ISD