Frankly, it has a lot to do with your floor. If you have a creaky wooden floor, it can be vey bad. Concrete is bad, but differently, and usually not as severe. If you have rugs or carpet, it's probably no big deal. If the drummer has a platform, it's easier to isolate the platform than the mic stands. I'll tell you, I would never put up good mics without shockmounts, but it has nothing to do with rumble. It gives the mic some protection from tip-overs and "flying stick" syndrome. Just for the protection they give the mic, they are worth it.-Richie