Angled room treatment?

Discussion in 'Pro Audio' started by Carey Carlan, Oct 8, 2005.

  1. Carey Carlan

    Carey Carlan Guest

    Sound reflecting off room treatments square to the wall would be parallel
    to the walls, floor, and ceiling. Would mounting treatments at an angle
    offer any benefit?

    Just a thought experiment. My parent's new house has rough pine planking
    mounted at 45 degrees across the walls of their living room. I was
    envisioning quadratic diffusers and bass traps aligned on that axis.
     
    Carey Carlan, Oct 8, 2005
    #1
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  2. Carey Carlan

    Chris Whealy Guest

    Rotating a wall mounted bass trap may look nice and aesthetic, but it
    will have no effect whatsoever on its acoustic performance.

    The effect of rotating a QRD *may* affect your perception of the sound
    depending on the operating frequency of the QRD, and the number of QRD's
    being used and the room volume.

    Most QRD's are one dimensional; that is, they are designed to scatter
    sound in the plane perpendicular to the direction of the wells. So if
    you wall mount a 1D QRD with the wells aligned vertically, you'll get
    scattering in the horizontal plane. Conversely, if you wall mount a 1D
    QRD with the wells aligned horizontally, then you'll get scattering in
    the vertical plane perpendicular to the wall.

    The proportion of sound arriving at the listener in the horizontal plane
    (known as the Lateral Fraction) makes a significant contribution towards
    our perception of the listening space. Terms such as as "warm" and
    "intimate" are often used to describe rooms where there is a high
    lateral fraction. These effects are contribute towards "Listener
    Envelopment".

    Mounting a single 1D QRD horizontally (i.e. to cause vertical
    scattering) will not provide any effect that contributes towards
    listener envelopment. Mounting it at 45deg will obviously be a halfway
    house.

    There are 2D QRD's available that have been designed to scatter sound in
    both the vertical and horizontal planes. Therefore, their orientation
    on the wall makes no difference to their acoustic performance.

    If you don't like the visual appearance of a QRD, then you can always
    stretch some open weave fabric, such as muslin or hessian, over the
    front to hide the wells. A fabric facing will not significantly alter
    the acoustic performance of the QRD, as long as you choose a fabric with
    a reasonably open weave.

    Chris W
     
    Chris Whealy, Oct 9, 2005
    #2
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  3. Carey Carlan

    Carey Carlan Guest

    Is this correct?
    A 1D QRD looks like a series of vertical slats with irregular depth front
    to back but all the same height.
    A 2D version has square blocks of differing depth.
     
    Carey Carlan, Oct 9, 2005
    #3
  4. Carey Carlan

    Chris Whealy Guest

    Your observations are correct, but it appears you don't understand how
    these devices cause sound to be scattered.

    Please read
    http://www.acoustics.salford.ac.uk/research/arc/cox/interdisciplinary/inter_science_reviews.pdf
    for a brief introduction to the topic. Then check out the Encyclopaedia
    page at the same website
    (http://www.acoustics.salford.ac.uk/acoustics_world/encyclopaedia.htm),
    particularly the page on why lateral reflections are important.

    Chris W
     
    Chris Whealy, Oct 10, 2005
    #4
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