In Reply to: How to stop a sheetrock wall behind speakers from resonating posted by Frihed89 on September 30, 2012 at 13:45:13:
Walls that sing along with the music seems to be a more common problem than I ever imagined. I would not have guessed a wall as dense and heavy as drywall would vibrate to an audible level but I'll take your word on it. I had a similar issue with old wood paneling which is much, much lighter and sang along to upper bass and low-mid frequencies.
After much research and reading F. Alton Everest's 'Master Handbook of Acoustics' (which I highly recommend) I decided upon the following treatment which worked very, very well BTW.
Using 1x6" pine ripped down to 1 by 4.5 inches, I built 8 frames 24x48" to accommodate 2 foot by 4 foot by 1/8 inch thick wallboard. I mounted the empty frames on the back wall (4 panels) and two each on the side walls near the corners where the back wall and side walls meet. I used simple L brackets and caulked between the frame edges and the rear wall making an air tight seal. Next I filled the frames with 4 inches of rigid fiberglass insulation leaving 1/2inch of air space between the fiberglass and the wallboards which were caulked and nailed down to the frame. These eight panels had now become resonators which absorb vibrations of quite a large frequency band and convert this energy to heat. The frames themselves I found firmed up my singing walls considerable even before I added the fiberglass, etc. but the finished product was far better.
This project turned out so well that I built some bass traps as well from rigid fiberglass formed for large pipe insulation like in a steam plant. I used 17 inch outside diameter pipe wrap filled with rockwool insulation.
One of these in the corners behind my loudspeakers and one in each corner across the room changed the sound of my space incredibly. My room nodes still exist but are nothing like they were exhibiting tight, clear bass notes with little or no overhang and my sing a long walls are gone. Total cost was around $500. which is a lot cheaper and easier than ripping out old walls, building new wall or buying new loudspeakers which I am sure would exhibit the same problem.
Simply adding another layer of drywall may alleviate the problem somewhat but I think the frame work behind the drywall is vibrating as well so I believe my system will work better since it absorbs the vibrations instead of transmitting them elsewhere.
Best of luck with your problem. Cheers.
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Follow Ups
- RE: How to stop a sheetrock wall behind speakers from resonating - finnman500@hotmail.com 09/30/1218:18:38 09/30/12 (1)
- A note about sheetrock walls - vinyl survivor 19:42:09 09/30/12 (0)