Need help with HT layout in basement

Discussion in 'Home Theater Projects' started by Rudolph V, Dec 6, 2003.

  1. Rudolph V

    Rudolph V Extra

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    I currently have my budget level HT setup in my finished basement, but I'm not that happy with the sound quality. I'm getting quite a bit of low frequency reverberation (booming). I need some suggestions from the infinitely more knowledgeable gurus over at this forum on how to improve the sound quality. At this point I can at most move things around in the basement and possibly cover some walls with fabric.

    Here is the basic layout of my basement:
    [​IMG]
    Note the location of the dry-wall walls and concrete block walls.

    I currently have my HT system setup according to the following layout:
    [​IMG]

    Here is one alternative layout I can do:
    [​IMG]

    Any suggestions on what the best layout for that space will be?

    Thanks.
     
  2. Wes

    Wes Screenwriter

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    Well since no one else has replied I will, I think your current set up is the best as the alternative drawing would be squishing your front stage big time. If I were you I would work on taming your subwoofer by moving it or Eqing it to fit the room acoustics. I think you have made the best with what you have now it's time to tweak the room acoustically.

    Wes
     
  3. Rudolph V

    Rudolph V Extra

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    Wes,

    Currently I'm getting quite a bit of reverberation though. Possibly due to having my listening postion close to the back wall and my speaker positions close to the front wall and the distance between the walls being close to one of the major wavelength modes of the low frequency responce of my audio system.

    I originally tried a layout as shown below:

    [​IMG]

    This layout, although not very convenient for the physical space, seemed to have had better accoustic properties.

    What would be the best location for the sub-woofer to reduce the effect of standing waves and overly amplified low frequency responce?

    Thanks.
    R.
     
  4. Parker Clack

    Parker Clack Schizophrenic Man
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    I like your alternative layout. I would give that a shot and see if you are getting the same problems with the reverb. If so I would put the sub in different locations in the room, say to the far left corner. Also as Wes suggested you could try an EQ that you could use to balance the sub to your room.

    Have you set up the speakers with a DB meter yet?

    Parker
     
  5. John Gallimore

    John Gallimore Auditioning

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    RV,

    During a tweaking session in my family room I moved things around a bit and found the booming got worse when I had the sub part way along a drywall wall. I've found that once certain frequencies enter the drywall cavity they can create havoc.

    Can you flip your first layout so your sofa and surrounds are on the drywall wall and the mains/sub on the concrete block wall?

    J
     
  6. Rudolph V

    Rudolph V Extra

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    Parker Clark: I've only used my receiver's built in pink noise test tone and my 'ear' to fine tune the individual speaker gains. My receiver also has the option of specifying the exact distance to each speaker from the listening position.

    John Gallimore: I'll try and flip my original layout to see if works. Unfortunately the couch is a bit long and will block the doorway to the left.

    I'm going to also try the first alternate layout and report back.

    Thanks for the suggestions.
     
  7. Andrew Steel

    Andrew Steel Extra

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    Hi Rudolph,
    Moving subs won't affect the boominess much. The problem is standing waves in the room you are in and at low frequencies the speakers are effectively omnidirectional. You may be able to find a spot where it sounds good but thats no good if there is more than just you as the sound will vary with position. What you have to do is absorb the low frequencies that are a problem. This is not a matter of fabric or foam on a wall as the wavelength is too long. There are lots of resources on the internet for DIY low frequency absorbers. I can give you some if you need them.

    By my calculations you will have the first standing waves at about 38Hz, 41Hz and 62 Hz.

    Andrew
     
  8. Rudolph V

    Rudolph V Extra

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  9. Wes

    Wes Screenwriter

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  10. Rudolph V

    Rudolph V Extra

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    Hmmm... that window is west facing so late afternoon sun might be a problem. Interesting suggestion though. This way things are kept away from the dry-wall. Worth a try.
     
  11. Wes

    Wes Screenwriter

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    Black out the window if possible, this set up lets you add EX/ES which you would love! Play around with sub placement and it may just solve your problem. BTW what sub do you have?
    Is there anything hanging on the brick walls? You may want to hang a rug or cutains on it to help knock down sound reflections. I dont think the sheetrock walls are the problem it's most likly the block walls.

    Wes
     
  12. Andrew Steel

    Andrew Steel Extra

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    Hi Rudolph,
    I can't post messages with URLs but the info you want is all there. I think this is a legitimate post so try to go to


    recording.org/users/acoustics/

    with the usual prefix

    Andrew
     
  13. PhilBoy

    PhilBoy Second Unit

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    Give your sub a twist so that it is not square to any wall.
     
  14. Rudolph V

    Rudolph V Extra

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    Never though of that one. Will it make a difference though? I though subs are pretty much omni-directional.
     
  15. PhilBoy

    PhilBoy Second Unit

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    A slight twist worked for me.

    Try it. Nothing to lose. 10 to 20 degrees should do it.
     
  16. Parker Clack

    Parker Clack Schizophrenic Man
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    Rudolph:

     
  17. Rudolph V

    Rudolph V Extra

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  18. Parker Clack

    Parker Clack Schizophrenic Man
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