I have a Sony STR-DE595 receiver which I believe has a default setting of 120Hz (non-adjustable unless set large) on "small " with the line level hookup to the sub. Volume setting for sub on AVR -3. I have been advised to turn my KLH sub x/o all the way up. Volume at 9 oclock positon (quarter turn). Sound level meter calibrated at 80-81db with other speakers at 75db. Bass is a little boomy, especially when turned up for DD2 movie or music mode. I want to stuff it with polyfill, fiberglass or foam but dont know how or which one to use. Radio Shack had none but they said go to CC for special stuff. Can someone please tell me what to get and how to do it? I realize that this is not the best sub on the market and I want to try to tweak it as best as I can. Any thoughts on my settings would be appreciated too. Room size is 11"X10". Thanks.