enclosure help

Discussion in 'Home Theater Projects' started by MikeHeath, May 6, 2003.

  1. MikeHeath

    MikeHeath Extra

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    I am attempting to build my first enclosure for a 10" sub. I have dowloaded and tried some sealed and ported enclosure spreadsheets. I was wondering what is better, sealed or ported. I have read many who say sealed. Also when I do the calculations I get a result of .50 cubic feet for size. That does not sound right to me. That would be aprox. a 12" x 12" x 6 enclosure. 6 inches does not sound like a proper depth considering the depth of the sub is 4 3/16" . Can anybody give me any help or input?

    Thanks in advanced
     
  2. Jeff Rosz

    Jeff Rosz Second Unit

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    and who made this 10"sub? whats the model?
    looky looky
     
  3. MikeHeath

    MikeHeath Extra

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    it is a 10" mtx 6000, 8 ohms, etc.

    Thanks
     
  4. MikeHeath

    MikeHeath Extra

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    it is also for home use, not car audio
     
  5. Dan Hine

    Dan Hine Screenwriter

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    [​IMG] I can't find any T/S parameters for an MTX home sub driver. Lots of Car woofers though. You wouldn't happen to have the T/S specs would you?
     
  6. MikeHeath

    MikeHeath Extra

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    they are for the mtx 6000 series. They are probably for car use, but was hoping to experiment with them as home use. I have all the specs if you need them.

    thanks
     
  7. Dan Hine

    Dan Hine Screenwriter

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    Definitely more suited for car audio. The size enclosure it would have to go in for flat response down to even 20hz puts the driver in position to bottom with only 75-100watts of power. And at that level the output just isn't very high (would benefit highly from 20db of cabin gain...again pointing to the fact that it is a car audio driver). I doesn't look like a bad driver if you want to put it in your car, but I'd really look for something else for your home.

    But that is just me. [​IMG]
     
  8. MikeHeath

    MikeHeath Extra

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    thanks for your advice, but I would really like to experiment with this driver for home use. Just an experiment of mine, but I am just thrown off by the dimensions i got from the spreadsheet.
     
  9. Brian Bunge

    Brian Bunge Producer

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    What about the dimensions is throwing you off? A 12" x 12" x 6" enclosure is .5ft^3. You don't have to use those exact dimensions though.
     
  10. Dan Hine

    Dan Hine Screenwriter

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    Mike,

    I must be using different numbers than you. Could you post the specs for the sub you have? I'm not getting anything near that small a box size to look halfway decent. Also, what program are you using? Unibox, WinISD, other?
     
  11. Frank Carter

    Frank Carter Screenwriter

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    Here's some T/S parameters on MTX T61044a. Mike said it was an 8 ohm sub and this is dual 4 ohm, it's the only one that can be wired to 8 ohms so I gues this might be it.

    Fs: 30.9hz
    Vas: 40.1L
    Qts: .60
    Qes: .69
    Qms: 4.63
    Re: 1.58ohms
    Sd: 367cm^2
    Xmax: 9.4mm
     
  12. Dan Hine

    Dan Hine Screenwriter

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    Frank,

    Yeah, that's the one I used. Sealed, I like how it looks between 3.5 and 4 cubic feet. Vented seems to favor around 5cubic feet tuned to around 21hz. At least, that's what I like. [​IMG] All this leaves me very confused as to how Mike was getting .5cubic ft. as a suggested box size. [​IMG]

    Of course, either way, give it more than 100 watts and you're in trouble down low. Mike, I'd hate to see you damage your drivers...be careful!
     
  13. MikeHeath

    MikeHeath Extra

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    here are the specs and my mistake, I was using the 8" 4 ohm specs, but even now with these specs I get 20.41 cubic feet. That still sounds wrong.

    Thanks for everyones help.

    Vas34.510
    Qts0.680
    Qes0.760
    fs33.3
    Xmax9.40
    Qms 6.76
    Re 6.29ohms
    xmax 9.4mm
     
  14. MikeHeath

    MikeHeath Extra

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    Dan,

    What program are you using to get the specs that you did for the enclosure?

    thanks
     
  15. MikeHeath

    MikeHeath Extra

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    okay so I just used winISD to input some driver information and got some results that maybe I need some help with.

    I received a 33.5 l volume for the design.

    the dimenisions are as follows:

    w - 0.363 m = 14.37 "
    h - 0.559 m - 22.09 "
    d - 0.232 m - 9.21 "

    can i minipulate these numbers as long as they equal the same total ( take 4 inches from the h and add it to the d? )

    22 seems a little high to me, maybe I am wrong and it is exactly right.

    also 33.5 l = 1.2 cubic feet. 1.2 cubic feet give aprox 14" by 14" by 10.7 ". How is that so off of the other dimensions?

    hope all this makes sense and forgive me if it does not.

    Thanks

    Mike
     
  16. Patrick Sun

    Patrick Sun Moderator
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    You have to arrive at the same internal volume with the changes in the dimensions (W x H x D). You can't simply add length in one dimension, and subtract it from another. Use your algebraic/geometry skills.

    The internal volume is a fixed value. Pick the 2 other dimensions to your desired lengths, and the 3rd dimension much be the (internal volume)/(dimension 1 x dimension 2).

    (Note - I've merged both threads on the same topic into one thread).
     
  17. MikeHeath

    MikeHeath Extra

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    Maybe this would be an easier way if anyone is willing to help.

    I will post my specs for the speakers and any experienced cabinet makers maybe can give me what their dimensons would be based on these. I am getting confused by different results I am getting and I have never attempted this before so any input would be greatly appreciated.

    Vas130.000
    Qts0.320
    Qes0.450
    fs26.0
    Xmax7.62
    Dia.30.48
    PEMax250

    Constants
    Ro1.18
    c345.00



    Enclosure Specifications
    Desired Qtc0.60
    Qr1.88
    Vr2.52
    Vb51.68
    Fb48.8
    F358.9

    Sd7.30E-02
    Vd5.56E-04
    n00.005
    SPL88.9
    K10.741
    K2110.696
    Amax1.000
    Par0.741
    Per151
    PeakSPL113

    thanks for your time and help

    Mike
     
  18. MikeHeath

    MikeHeath Extra

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    so i have spent all afternoon researching, playing with numbers, etc. and have come to a reasonable ( I think) calculation.

    1.82 cubic feet which equals 3144.96 cubic inches

    a 12 " x 15" x 18.75 " (golden ratio included) enclosure equals 3375 cubic inches.

    I read up to a 20% difference would not make a noticable difference.

    do these dimensions make senses according to the above t/s parameters?

    thanks for info!
     
  19. Brian Bunge

    Brian Bunge Producer

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    Mike,

    It's not necessary to use a golden ratio enclosure for subwoofers. If the 1.82ft^3 enclosure gives you the Qtc you are looking for then that is the box you should use.
     
  20. MikeHeath

    MikeHeath Extra

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    are you saying i can use any three dimensions as long as they equal the 1.82 cubic foot total?
     

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