No parallel surfaces in a theater

Discussion in 'Archived Threads 2001-2004' started by Bill Catherall, Sep 7, 2001.

  1. Bill Catherall

    Bill Catherall Screenwriter

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    I've been thinking about acoustic treatments and wondering how much it would improve things to have non-parallel surfaces in a home theater. I've drawn up some preliminary plans so I can get some feedback from everyone. I drew up the plans to scale using AutoCAD. You can view them http://wcatherall.homestead.com/files/theater/layout/layout.html
    [​IMG]
     
  2. Jens Raethel

    Jens Raethel Second Unit

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    Bill-
    Im no expert but it looks nice!
    I see some similaritys to my own project that I just finished. I had expert help in planning the acustic layout.
    You allways have to do some compromises, but the result went out very well!
    Take a look at my homepage under the "architect" page.
    Good luck!
    Jens [​IMG]
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    Go see my new theater CINEMAX! updated 2001-08-27
    And PLEASE sign my guestbook!!
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  3. Bill Lucas

    Bill Lucas Supporting Actor

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    Bill,
    Room dimensions that are not multiples of each other or divisible by the same number are much more important than using non-parallel walls. Whether the walls are parallel or not you will have issues to deal with regarding room resonances. Check out Russ Hershelmann's fine series in SGHT for excellent mathematical information about proper room construction and placement of speakers. Good luck.
     
  4. Deane Johnson

    Deane Johnson Supporting Actor

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    Bill, I won't comment on the acoustical properties other than to say they would have to be much, much better than parallel surfaces.
    What I really like is the visual effect of this type layout. I saw a HT designed this way a couple of years ago and the effect is striking. If I were working with space that allowed this approach, it is the only way I would do it.
    Deane
     
  5. Tom Vodhanel

    Tom Vodhanel Cinematographer

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    The dimensions of the room(along with the speaker/sub and listener positions)will dictate the mode issues to a much larger extent than worrying about non-parallel boundaries.
    TV
     
  6. Bill Catherall

    Bill Catherall Screenwriter

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    Thanks for all the feedback so far.
    Bill Lucas, I'm not familiar with what SGHT is.
    Bill and Tom, I would think that no matter what the dimensions of a cube shaped theater, you will always get some standing waves. Or do you "tune" the room so that any standing waves you do get will be absorbed by other wall treatments?
    Deane, I too like the visual appeal of a "non-cube" room regardless of audio enhancement.
    Of course, all this depends on space, and when I get the space I may be forced into going with some cube shape and work around the problem similar to the way Jens did.
    Again, thanks, and keep it coming!
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    Bill [​IMG]
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  7. Mac F

    Mac F Agent

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    I'm not sure exactly how non-parallel surfaces would work for home theater or music listening. The concept has been used in auditoriums for quite a while. Many many years ago I was in the auditorium at the Bell Labs in Murry Hill, NJ. One speaker mentioned that there were no parallel surfaces which improved the acoustics. I remember that it was a fair sized room and none of the speakers used a microphone. That was some time before I discovered hifi or stereo imaging, and we weren't given any recorded demonstration.
    A few years ago I was shopping at a hifi store in the Dallas area (Audio Insight, I believe). The salesman commented that one of their listening rooms had been built with non-parallel walls. He said that it didn't completely remove resonances, but made it impossible to predict them. The store was in the process of rebuilding the room. I didn't have time (and the salesman didn't offer) to evaluate the room for resonances and standing waves. Some standing waves are axial (parallel walls) and some are oblique and tangential, these are said to be less importance. I would love to hear from someone who has had real world experience.
    SGHT is Stereophile Guide to Home Theater magazine, for the past two years they have had a column 'Home Theater Architect' which explores in a very informative, but non-technical manner, how to avoid sound problems in a very expensive home theater. It is not intended as a DIY column, but there is excellent information.
     
  8. Bill Lucas

    Bill Lucas Supporting Actor

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    Bill,
    Either way you are going to have room mode problems. I'd rather have fixed resonances (there is no such thing as a "standing wave") that I can deal with by mathematics and placement than random dimensions that change and can create MULTIPLE resonance issues (such as those created by non-parallel walls). Regards.
     
  9. Bill Catherall

    Bill Catherall Screenwriter

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    Hmm...thanks Bill. It looks like I'm going to be doing much more research. But I've got plenty of time for that.
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    Bill [​IMG]
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