a question about room acoustics

Discussion in 'Home Theater Projects' started by Rob Michaw, Jan 10, 2005.

  1. Rob Michaw

    Rob Michaw Stunt Coordinator

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    I am always tweaking my system and moving speakers around looking for the best configuration. Recently, I have started making my own accoustic panels and setting them up around the room.

    I have drawn a diagram of my room, and I have shown the panels in grey. The ones near my fronts are 2x4 (vertical), and the ones at the rear and the front are 2x2. The ones by the rear are placed under the rear channels (18" clearance from the top of the rear to the ceiling).

    My room is carpeted, and I have Armstrong ceiling tiles (sound reduction). I have been able to get the front soundstage to disappear quite well, but the back of the room sounds a little too lively (or better yet...localized). When I am listening to DVD-A or SACD I am a little too aware of the rears. As I mentioned, I have room above the speaker to do some work, or I could do other things if suggested. I have a BFD equalizing my sub and bass response in the room is quite flat and the sub disappears quite well too.

    Any suggestions?

    [​IMG]
     
  2. dany

    dany Supporting Actor

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    Turn the rears down a notch.
     
  3. Wayne A. Pflughaupt

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    Rob,

    It would be easier to answer you question if you had given us info on your speakers – make model, direct radiating, bi- or dipolar, etc.

    Given your 12-ft. dimension for room width, I’m going to assume that your rear speakers are closer than your front speakers. Speakers in close proximity will always sound brighter than if they’re further away. That may be why they are drawing your attention. As such I suggest reducing their treble response.

    Regards,
    Wayne A. Pflughaupt
     
  4. Rob Michaw

    Rob Michaw Stunt Coordinator

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    Wayne -

    I am have JM Labs Cobalt 816 S up front, the SR 800 at the rear, and the CC800 for the center. I have a Paradigm PW-2200 sub.

    You are correct in your assumption of speaker distances. I am sitting 8.5 ft. from the fronts, and 6 from the rears. I too think that reducing their treble response could help (I was holding foam up near the speaker and it appeared to tame it a bit). What I need to know is what I should do...or at least what avenue to go down. My panels are DIY jobs, and would be more than willing to try some methods around the rears, but I need some suggestions.

    Thanks.
     
  5. Wayne A. Pflughaupt

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    Nice set-up you have there, Rob. [​IMG]

    The panels you’ve put up are intended to cut down on reflections and make the room less reverberant. Add to that the carpeted floor and ceiling tiles and your room probably has all the acoustical treatment you need – unless you’re going for that totally “dead” recording studio effect.

    That is a separate issue from your rear localizing situation, and nothing you do with the panels will change that problem. Since you say that holding foam near the speaker seemed to help, that’s what I’d pursue.

    If your receiver doesn’t have provisions for rear-channel equalizing, you can reduce treble response mechanically by covering the tweeter with some cloth. You’ll have to experiment with various densities to get the amount of reduction you need. Just keep in mind that the more light you can see through the material, the more it will pass high frequency signals, and vice versa.

    Regards,
    Wayne A. Pflughaupt
     

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