As I've posted before, I live in a 3 bedroom apartment with 2 roommates. Since building up a home audio system that's kind of overkill for the room, I've had some noise complaints from my wonderful roommates. (Well, actually one pain in particular!) It seemed when my subwoofer started to rumble, so did their bedrooms! I started out trying to isolate my sub with some racquetballs, which actually worked to a point, but the problem was still there.

Upon reading some Pro Audio magazines, I noticed a review for an Auralex product called a "GRAMMA." (Stands for "Gig & Recording Amplifier & Monitor Modulation Attenuator) It's made to be used under mainly guitar amps to control, well, interaction between the amps and the room or stage. It's also advertised to be used under any type of speaker. I thought it sounded like something that might fit my situation, so I got one.

Let me put it this way, it works!! I was actually able to turn up the volume of my subwoofer after placing it on the GRAMMA. It just "soaked up" all room resonance and rumble. Mind you, my room still shakes where it's supposed to on movie soundtracks. On lighter parts and music, however, all I get is clean, tight, solid bass. And, most importantly, my roommates feel less rumble.

If you have a need to clean up unwanted bass or if you need to isolate your speakers from the floor, I highly recommend this product. It retails for about $50. Here's the website if you want more info:
www.auralex.com/sound_isolation_gramma/sound_isolation_gramma.asp