Bests & Worsts Reviews from Amazon

These are very light density foam corner pieces that do not at all act as bass traps. As another reviewer said, they're probably only dense enough to dampen the highest frequencies. I installed 8 of these in the back corners of a little 9'dx10'wx6.5'h room and have attached before and after installation analysies taken from the central listening position. You can see that: (A) There is serious phase cancellation happening in the bass frequencies and (B) there was little to no change after installation. (Look at the red peak lines, not the green bars)