I have made four "ASC" type of traps, going by their diagram. They have helped with general slap back immensely, however, IMO, if you have a bass problem, you will need to go with either a parametric eq, or something besides ASC type devices. It all depends on your room. Some say any tone controls detract from the sound. I'm running all analog and even though I have many absorption panels, believe I either need to get a very expensive parametric eq, or make some diaphragmatic absorbers. I have a problem with 30-150hz. I've put so many panels of 1" 2x4 703 compressed insulation, I have begun to suck the life out of the music. I'm going to put some wood facing over about half of my panels and make a couple of diaphragmatic absorbers. IMO, if you have a heavy bass problem, anything else will be a waste of time and money. I'm very open to any suggestions. I have a good quality graphic eq in the mix( Samson S-curve 231), it just doesn't get the job done. My room is 19x21x10 and has 'knee" walls. I realize tone problem is my room dimensions-too square. I keep saying I need to post some pics, but don't have a wide angled lens. Equipment used: VPI Scoutmaster w/ DRT XV-1s cart, Theta Miles CD transport, Aesthetix Rhea Signature, Aesthetix Calypso Signature, Krell EV-600 monoblocks and a couple of Wilson Maxx II's. All suggestions welcomed!! As Milla Jovovich once said "please help."