Is the Tumult sealed?

Discussion in 'Home Theater Projects' started by Brian-K-Owens, Jul 22, 2003.

  1. Brian-K-Owens

    Brian-K-Owens Stunt Coordinator

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    Does the tumult driver itself leak air in a sealed box?

    I noticed that my tumult enclosures do not seem as sealed as other sealed setups I have done in the past. . .By this, I mean I can push the driver cone in by hand about an inch, and all of the air I have displaced is leaving the box somewhere. When I let go, the cone slowly moves back to resting position; not as much "springyness" as I would think there should be from past experience.

    The box is 2 layers of 3/4" MDF (2.5 ft^3 internal), and all joints are interlocked. The inside seems are sealed, then I coated all outside seems with liquidnails and went back and belt sanded them flat just in case there were any gaps. I cannot hear any air leaks, but there is definitely air leaking out somewhere. . .The driver is screwed in tight and I am using the rubber gasket. when I push the cone in, I cannot hear air coming from around the driver flange.

    Do this even matter? I have always tried to make sure sealed enclosures are VERY sealed.

    Thanks!
    Brian
     
  2. Chris Carswell

    Chris Carswell Supporting Actor

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    " When I let go, the cone slowly moves back to resting position; not as much "springyness" as I would think there should be from past experience. "

    Now Brian, think about this statement for a second. You should be able to answer your own question [​IMG] If you need help, go do the same thing to a ported enclosure & compare the results.....
     
  3. Wes Nance

    Wes Nance Stunt Coordinator

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    I have heard others say that they don't use the rubber gaskets that come on these newer subs, but remove themand use the regular close cell foam tape to seal in the driver.

    You need someone that's installed this driver to chime in, though. . .

    Wes
     
  4. Brian-K-Owens

    Brian-K-Owens Stunt Coordinator

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    "Now Brian, think about this statement for a second. You should be able to answer your own question If you need help, go do the same thing to a ported enclosure & compare the results....."

    Sorry, you lost me. . . .maybe my statement was not clear?

    Brian
     
  5. Arthur_King

    Arthur_King Stunt Coordinator

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    Uhhh... That doesn't mean anything Brian. In a "sealed" enclosure, the cone moves in an out ALL THE TIME. The air is 'compressed' internally and actually 'pushes back' on the cone. If you get an empty 2 liter soda bottle and squeeze the outside, it doesn't "leak" it compresses the air inside and usually pushes back out when you let go.

    Now, you say that the cone "slowly" moves back to its default position... That I dont know how to answer. It may very well be a leak around the gasket, you can get your own closed-cell foam or other insulation type material to mash in there and seal any small leaks.

    I dont know if your test is valid, but it couldn't hurt to put a different type of material around the sub edge.

    You could always try a "smoke test" with a cigarette, but the sub would probably be moving some decent air itself, so it would be hard to tell, maybe if you could "block off" all but an inch away from the baffle, and see if anywhere around the outside of the sub there is air "blowing" parallel to the front face of the sub box.

    Daffy Arthur King
     
  6. Brian-K-Owens

    Brian-K-Owens Stunt Coordinator

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    I think I confused people the way I posted this. . .

    If I build a "totally" sealed box, when I push the woofer cone in and let go, the woofer should move back into resting position with added force (other than just the driver suspension) due to the compressed air. Of course, if I held the cone compressed long enough, the air would escape, as I have found it impossible to build a "totally" sealed enclosure, but the cone would move back into position VERY slowly as air re-entered the enclosure very slowly.

    In the case of the Tumult setup I have, if I press in the cone and a instantly let go, I can tell that the compressed air has escaped from the box from somewhere, because the cone does not move back into resting position as though the air was compressed behind it. It moves back into position somewhat slowly as air re-enters the box from somewhere. . . .

    I will try the smoke test tonight to see if I can determine where the air is escaping. The box is very well sealed inside, and I cannot hear air or feel it around the gasket/mounting when I press the cone in, but maybe if it is leaking all the way around the driver that is enough to cause what I am seeing without hearing it. I just did not know if maybe something like the dust cap of the tumult was not air tight enough to make the test I am doing a valid test.

    Thanks,
    Brian
     
  7. MichaelAngelo

    MichaelAngelo Stunt Coordinator

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    Brian,
    I understand the problem you describe. Try baby powder, to find the leak.
     
  8. Jason Brent

    Jason Brent Second Unit

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    I don't know if today's woofers are the same, but I remeber about 10 years ago when I was in the car audio industry, there was a small pin hole on the dust cap of all our woofers. All sealed boxes that we used to build acted the same way as yours.
     
  9. Bryan Michael

    Bryan Michael Supporting Actor

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    if you were testing it when moveing lol my av15 can blow out a candle i put my hand near the woofer and it was amaseing the air i thought there was a leak but i have a ported box
     
  10. ChristopherD

    ChristopherD Stunt Coordinator

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    Huh?
     
  11. Craig Woodhall

    Craig Woodhall Supporting Actor

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    i know, i can't understand a word he says [​IMG]
     
  12. ChristopherD

    ChristopherD Stunt Coordinator

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    i guess i just don't speak irish
     

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