Standing Waves? Room Modes?

Discussion in 'Archived Threads 2001-2004' started by Christian Speights, Jan 30, 2002.

  1. Christian Speights

    Christian Speights Stunt Coordinator

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    I just have no idea what these are. Can anybody here help me out? I am tired of being ignorant...I want to learn.

    Please show me the way...
     
  2. Dave Dahl

    Dave Dahl Stunt Coordinator

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    Ok, here we go...

    I only have a minute to write. When sound is created from your speakers air moves from the speaker drivers into the room. When it reaches you ears the brain reconstructs the moving air waves as sound. However the sound waves do not simply move directly to your ears. It also bounces off of the ceiling, floor, and walls. When these refections begin the interact with other sound reflections the frequencies of the sound can be affected. These are called standing waves. Depending on all kinds of variables you will have many different effects. Certain frequencies will be louder or softer than originally intended. Not just that but as you move around the room those frequencies affected will change. Very tricky stuff. There are some good rules of thumb to help tame these type of problems. Non-parallel wall in the room help. So does keeping the speakers and subwoofer placed in the room at an odd fraction of the length or width. 1/3 or 1/5 the length of the room for example.

    There are ways to graph possible standing wave issues in your listening room but alas I have run out of time. I am sure that others on the forum will help.

    -Dave
     
  3. Bob McElfresh

    Bob McElfresh Producer

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    A good book is "Sound Studio Construction on a Budget" by F. Alton Everest. It will take you through a lot of the different theories about room interactions, and suggest practical treatments.
     
  4. Christian Speights

    Christian Speights Stunt Coordinator

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    Thanks for the tips gentlemen. I will have to check out that book for sure.

    I have some gaps in the frequency response of my system that have lead me to believe I am not as good at calibration as I had hoped.

    :b
     
  5. Alan Pummill

    Alan Pummill Screenwriter

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    About a year ago, I installed Sonex acoustic tiles between my mains (behind the TV), and on both side walls at their main reflection points. It really tightened up the bass, and improved the soundstage of my system. My HT room is 20' X 24', and I was experiencing the same problems Christian was.
     

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