Posted by Lew on October 08, 2002 at 11:02:28:
In Reply to: Re: I am not sure I understand you, but... posted by Terry Koehn on October 08, 2002 at 10:35:57:
my ears. The sound was pretty awful without anything to absorb SOME of the rear radiation, so I designed and built the total of 4 panels, two per side. I used one-half inch plywood to which I affixed sound-absorbing ceiling tiles, the kind with irregular pits in them. Over the ceiling tiles, I tacked some 2-inch Sonex foam. Then I covered each panel in beige burlap for the sake of cosmetics. After installing the panels, I still had the aforementioned bass problem. The bass was boomy and indistinct at 50 to 200 Hz (somewhere in there, and this was with my original set of U2s). Then I discovered the benefits of a very dense and physically irregular sound-absorbing element in the form of those antique rosewood chairs. Still there was a slightly irritating peak at ca 2 to 4kHz. I built a 5th panel of the same materials, about 1X7 feet in size, and installed it in one corner of the room behind my listening position, so as to absorb any reflection occurring between the side wall and the rear wall at that junction. (There is a large open entryway at the opposite corner in the rear, so reflection was not an issue there.) This worked great with U2s. Works well with M1s too, except now I think a little diffusion of sound bouncing off the rear wall would be beneficial. (The M1s can generate so much more sound pressure than can the U2s.) Hence my thoughts about RPG diffusors. I don't want to deaden the room any further.