Diffusion versus absorption behind speakers?

I was told to try some wool carpets or blankets behind my speakers to keep my downstairs neighbor happy. I tried some thick 2.5' X 3' cotton rugs behind my speakers and she can't hear a thing now. If it can keep the sound from running down the walls (and I do play it loud at times), then one can imagine how it 'tames' reflective sound.

I've tried both absorption and diffusion behind my speakers at the front wall and in the end removed them and now don't use anything behind them. Instead, the corners are treated with bass traps, the upper corners with Eighth Nerve triangles and the seams where the ceiling meets the wall with Eighth Nerve rectangles. Unfortunately Eighth Nerve is no more, but their concept on how to treat rooms is very effective for me.

As previously mentioned one can eliminate many room interactions by listening near field, which due to my room configuration is really my only option. You might also want to post this over on AA. There are some great resources over there, especially David Aiken, who have helped me address this issue, especially the best methods to use diffusion.

Thanks Clio. I think your approach is making more sense to me. Leave the front wall alone and treat the corners of the room and possibly side wall first reflection point.

I am using diffusors from Core Audio Designs behind my speakers. The speakers, which are a front radiating cone design, are just 28" from the front wall (measured from the tweeter), due to space limitations. Adding the diffusors behind my speakers increased perceived resolution, added depth to the soundstage, made the speakers less localizable, and enlarged the image sizes.

I also experimented briefly with absorption, but in my setup, the only improvement was increased perceived resolution. Soundstage depth, speaker localizability, and image size either stayed constant or got worse. I'm not sure what the results would have been if my speakers were farther away from the front wall, but I suspect it would have been similar in kind while less in degree.

The Core Audio Designs diffusors are also among the most attractive room treatments I have seen. I have no connection to the company.

Good luck.

One of the pieces of advice I received regarding diffusion is that the larger the room, the more effective it is. Makes sense considering that diffusion works by spreading the sound around.

These are the diffusers I used:

http://www.decware.com/newsite/room.html

There is some good information on acoustics and room treatment from Decware too.

The Core Design diffusers are extremely nice. Wish I had the space to try those out.