Enclosure shape

Discussion in 'Home Theater Projects' started by JoeFish, Jul 29, 2003.

  1. JoeFish

    JoeFish Stunt Coordinator

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    Hello all. I've buit a few subwoofer enclosures, and I'd like to move on to home theater speakers. Specifically, a LCR set.

    So, to save myself a lot of calculations, I'm going to start with one of the commercially available kits.

    I was wondering how important the shape of the box is to the operation of the speakers. ie, if I purchase a kit that is designed to work properly in a rectangular box of a certain volume, will the response of the speaker change if I build a trapezoidal box of the same volume? Or what if I make the box shallower and wider than the original design?

    Thanks for any input!

    -Joe
     
  2. Joe Ku

    Joe Ku Stunt Coordinator

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    Here is how I understand it, someone correct me if I am wrong. The front baffle has to be the same width as the plans show, but the height and depth can be altered as long as the volume stays the same. If it is ported the end of the port should be at least one port diameter away from the side of the enclosure.

    I modified the Audax ht to suit my needs using these guidelines and I think they sound great.

    http://www.angelfire.com/music5/hometheater/
     
  3. ThomasW

    ThomasW Cinematographer

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    Keep the front baffle the same height, width, and 'shape'.
     
  4. Joe Ku

    Joe Ku Stunt Coordinator

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    If you keep the front baffle the same height and width that would imply the depth must also remain the same (assuming a rectangular prism). I have seen many speaker builders change the height of the baffle without hurting the sound of the speaker. I know width is related to the baffle step built into the crossover, but how does the height effect the sound quailty?
     
  5. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    Joe, the top edge of the cabinet is another edge, just like the side edges, so it contributes to baffle step too.
     
  6. TimForman

    TimForman Supporting Actor

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    Hank & Thomas, wouldn't driver placement compensate for the change in height? i.e. If you make the baffle higher wouldn't you maintain the driver distance from the top?
     
  7. ThomasW

    ThomasW Cinematographer

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    If the baffle height is modified by making the cab taller/shorter; or if the driver's placement is changed on the baffle, the baffle step compensation will likely change.
     
  8. JoeFish

    JoeFish Stunt Coordinator

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    OK, so if I maintain the front baffle shape and size, and the same enclosure volume as per the plans, I can modify the shape of the enclosure behind it and not affect the tuning of the box?

    For example, could I make the enclosure shallower, and slope the sides to make it wider, keeping the front baffle exactly the same?

    -Joe
     
  9. ThomasW

    ThomasW Cinematographer

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