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Absorb or Diffuse Behind Listening Position?

Hey All. Starting to finally treat my listening room. My listening position is up against the rear wall (head probably being spaced about 12" from the wall when sitting down). I’m putting 2’x4’x2" absorbing panels behind the speakers, but what should I choose for behind the listening position? Diffusion or absorption?

There are al lot of windows in the room, with horizontal louvered shades which act as pretty decent diffusion; and a big built-in bookshelf on one side wall also helping with diffusion. On either side of the wall behind the listening position are a pair of glass French doors, untreated at this point, and the room sounds a lot better when they are left open to the big room on the other side of the wall. I haven’t tackled the ceiling yet either. Thanks!
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rodge827's avatar
rodge827
619 posts
 
Here is a room calculator to find where your first reflection points are and the size of absorption panels you’ll need. Just punch in your measurements in inches, feet or meters.

https://www.acoustic.ua/forms/calculator4.en.html
arion's avatar
arion
160 posts
 
The treatment of a sound room is not generic. Bass issues are largely determined by the room dimensions and size. Using bass traps (real bass traps) is almost always beneficial. Moving into the mid and high frequencies, the treatment often depends on the speaker placement, type of speakers, wall covering, floor covering and furniture. Real diffusors should not be placed directly behind the listening position. The listening position should not be close to any real diffusors. How close depends on the type of diffusion and possibly room size. Minimum 5 to 6 feet. Place absorbers behind you and avoid over-damping as stated previously.
bdp24's avatar
bdp24
9,814 posts
 

For a diffuser to work, it has to be a "certain" distance from the listener's ears. I put certain in quotes because the distance is frequency determined. A Google search will lead you to the related data, but start with the YouTube videos posted by Acoustic Fields.

Your ears being only 12" from the rear wall (or even twice that), I would say diffusion is out. Simple Owens Corning 703 panels (covered in material of your choice) is a good choice, the 703 being what almost all commercial makers of absorbers (GIK, ASC, etc.) use.

mijostyn's avatar
mijostyn
8,570 posts
 
summadoggie, that is one of the worst listening positions you could have for a number of reasons. You can use absorbers behind you but that will do nothing for the bass which will be exaggerated by up to 6 dB.  You need to pull yourself at least three feet away from the wall. The best listening position is always somewhere towards the middle of the room. 
rodman99999
6,156 posts
 
What mijostyn said +1, but for the middle of the room position.    My present seat is right at 35% of room length, from the back wall, with Auralex absorption and LENRDs behind me.    Diffusion behind the speakers.    Some tips: (http://arqen.com/acoustics-101/room-setup-speaker-placement/)     and: (https://www.gikacoustics.com/basics-room-setup-acoustic-panels-bass-traps/)
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