Resonance chamber?

Discussion in 'Home Theater Projects' started by Jason Padrick, May 13, 2003.

  1. Jason Padrick

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    Hi guys,

    This is actually my first post here, and this may be a noob question too, so bear with me. I am interested in building speakers, but haven't yet (my dad's K-horns rock though, I know that much).

    In large auditoriums I've heard of a term "resonance chamber" used in order to increase the bass output in a hall. I was wondering if the same idea could be used in a room, using an open ended box of some sort. I think if this was put in a high-ceilinged room it could work. I've searched these forums and can't find anything on it, and it's hard to find some info Googling for it. Any ideas?
     
  2. Arthur_King

    Arthur_King Stunt Coordinator

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    Im not sure what you're referring to.

    Do you mean something like the HornLoaded subwoofers people have made?

    Like the
     
  3. Cam S

    Cam S Screenwriter

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    Arthur, those links don't work and nothing but popups come up and they are a bugger to get rid of, ya might wanna edit them.
     
  4. TimForman

    TimForman Supporting Actor

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    Uh, the second link worked for me (not the first one though) and the Royal Device compression chamber is amazing. 100 db at 6 meters with 1 watt? OMG!
     
  5. Jason Padrick

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    Wow, that's a HUGE horn. Think of the group delay....

    The resonance chamber I was thinking of has no active drivers. I think it's just an open box in the roof. Just to help amplify live musical performances.
     
  6. TimForman

    TimForman Supporting Actor

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    This sounds like resonance boost which requires some serious math calculations using wavelengths, room dimensions, etc..I bet a course in acoustical engineering would help you find the answer. [​IMG] Seriously though, there is a lot to be gained by "tuning" your room. Not an easy task, but interesting. You could continue Googling for "room acoustics". Might find something useful.
     
  7. Jason Padrick

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    These resonance chambers I was talking about I think are what you are saying Mr. Forman. These chambers are big enough for people to stand in. I should look for an acousitcal engineering course at school when I'm in upper division. Sounds interesting.
     
  8. Brett DiMichele

    Brett DiMichele Producer

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    Tim is right..

    Those Resonance Chambers are tuned to boost specific
    frequencies and it would take some major work both in the
    room and mathmaticaly to get it right. Your best bet it to
    get the room as acousticaly inert as possible then check
    the total ouput of your system at every frequency and if
    you need to equalize from there you can do so. The goal is
    flat (I am guessing that's what you want) you can easily
    equalize a subwoofer with a Behringer Feedback Destroyer
    and dealing with midrange and trebbel is done via careful
    positioning of the mains and eliminating the first and
    second reflection points either from use of acoustic
    pannels or something more creative (diffusors, bookcases)
    Tapestries, paintings etc..

    Also if you really have room mode issues with bass that the
    BFD doesn't remedy then you can DIY your own Bass Traps.
    Our resident Gomer (Anthony Gomez) has done some very nice
    Bass Traps for his listening room.
     
  9. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I think "Helmholtz" resonators is what Jason is talking about.

    I guess they are chambers with a neck and opening that "resonate" at certain frequencies much like a coke bottle. They can also be built as a slotted wall to do the same thing.

    IMO, the bass traps will not effectively "increase" the bass in your hall that much. Instead, they level the frequency response of the room by raising/lowering the dips and peaks depending on the tuning frequency.

    An easier bass tuning treatment is an absorbing bass trap that physically slows the air movement down in the high pressure corner regions of a room.

    Not long ago I made some nice bass traps that helped flatten my room's frequency response.
     
  10. Brett DiMichele

    Brett DiMichele Producer

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    Chris,

    Who are you trying to B.S here?

    Everybody knows that the Hemholtz Resonator was used
    on Deck 20 in Jeffrey's Tube C9 on the U.S.S Class D Enterprise!

    Beam me up! [​IMG]
     
  11. Pete Mazz

    Pete Mazz Supporting Actor

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    AFAIK, what you're talking about is like a Helmholtz resonator, except made from concrete or ceramics to enhance the output. Problem is, they have a high Q and therefore ring quite a bit. Most of us are trying to remove these types of resonances from our rooms, hence the use of treatments or EQ.

    Pete
     
  12. Jason Padrick

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    I think a Helmholtz resonator sounds like the same idea. But if it rings why would they use it?

    Could they be made of wood?
     
  13. Aaron_Morris

    Aaron_Morris Stunt Coordinator

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    Just FYI the first link will work if you erase the "< a" at the end.
     
  14. Pete Mazz

    Pete Mazz Supporting Actor

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