Cinder Block Walls

Yup, but jusdicous damping of the walls with accoustic foams or fiber glass does wonders. When you add furniture it helps break up some of the reflected bass. It also deadens the room to a remarkable degree. Hanging heavy carpets about 2 inches from the wall also helps.

Get creative and don't spend a lot of money.

Also stuff those joists with the new corning pink stuff in the plastic sheaths. I wouldn't recommend using straight glass without a barrier for health reasons.

Also 1X4 frames with 4-6" glass covered by printed sheets stapled to the frames make dandy absorbers. Position about 4 inches from the wall. In the corners use the 8" thick and use 1X8's and place at a diagonal. Build them about 3 foot wide for nice corner bass traps. Cover them with sheets as well. I use nylon mesh screen over the glass, and then cover with decorative bedding sheets with a pleasing print. Low bucks and work like a charm.

The basement is the best place for audio.

jeff

Rives, thanks.

To clarify, all 4 of the walls are bare cinder block. The ceiling is unfinished with exposed joists. The room will be dedicated to audio and I'll have the flexibility to position everything for optimum sound quality. The room will be sparsely furnished, just the audio equipment, records and a listening chair. I figure between the main speakers, the twin RELs and the TACT EQ I can deal with bass peaks, but I'm worried about the room being overly hard and reflective.

The biggest problem is when two walls are cinder block and you get an imbalance. A three layer buildup on the wall with out the block and adding furring strips, insulation, and sheetrock on the block wall will help. If the block is behind the speakers it will help reinforce the bass--sometimes too much, but if you are planning to use the entire area as a listening room I don't expect that to be a big problem. You will have a domiminent bass peak based on the floor to ceiling height since that is by far the majority of the area of parallel surfaces (and the others are so far apart). Ceiling diffusion will be a big issue for this reason, very likely more so than the issues with the concrete block. Give us a call and we may have a few tips to help you out.