Using Batting in Tempest Sono

Discussion in 'Archived Threads 2001-2004' started by DaveNaumann, Sep 19, 2002.

  1. DaveNaumann

    DaveNaumann Extra

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    Hello everyone, I'm just about finished with my tempest sonosub. I have a quick question. I've sort of been trying to follow the alignment plans, however I increased the volume to 240L. Anyhow, Adire recommends 64oz of polyfil. I bought one bag of batting at Walmart. It is one 110"x110" sheet that is 1/2" thick I plan on lining the inside of the tube a few times to use all of the batting up. It doesnt say anywhere how many ounces the sheet is. Do you think that is enough or should I get another bag of batting to stuff the tube with? I dont want to use regualr loose polyfil because I dont want it blowing out of the port. Thanks in advance for any advice, this group is the best!

    Dave
     
  2. Patrick Sun

    Patrick Sun Moderator
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    You could weigh it and see if it's 4 pounds (64 ounces).
     
  3. Mike Strassburg

    Mike Strassburg Second Unit

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    Small postal or UPS scale would be the most accurate.

    Apply to inside with some spray glue and you're set...
     
  4. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Good point, My tempest shoots out (fluffed) poly fil like mad when I do bass test, I gotta jerry rig something so the polyfil doesn't reach or block the ports.

    The huge benefit of using fluffed polyfil is that walmart sells a 5lb box of premium fiberfil for only $7.43.

    Back to the topic:

    An easy/crude method would be to stand on a weight scale and weight yourself, then pick up the polyfil and weigh yourself again. If it's within 1-2lbs then I think you're safe. 4lbs is actually a LOT of polyfill that filled my smaller 214L box to the brim.
     
  5. Robin Smith

    Robin Smith Stunt Coordinator

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    I sort of asked this question before but didn't get a clear answer.
    I have a complete 214L Dayton 15" DVC sonosub tuned to 15.4Hz with a single 4" flared port. I lined it with one layer of batting, but added no more stuffing.
    What would be the change if I were to stuff it with some polyfill. How would it change the sound. Does it have the same effect as if I had simply increased the volume or does it do something more?
    When I put the numbers in the Adire program it lowers the tuning. In my calculations what does 10% fill equate to in weight, cos I don't think I stuffed 10% in there with the one layer of lining I used.
    Also, does it matter if the polyfill is all at the bottom or should it be spread evenly. In my design, the polyfill would fall down and sit on the sub driver's back since the deisgn is downfiring. What prob.s would this cause?
    My sub: http://www3.sympatico.ca/robin.smith1/Sonosub
    Thanks
    Robin
     
  6. Bryan Michael

    Bryan Michael Supporting Actor

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    look on the bag it usaly tells you how much it weighs i put 64 oz if polly fill in my 250l what it dues is lower the tuneing point caues i moddled mine with no fill
     
  7. Joe Tilley

    Joe Tilley Supporting Actor

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    Robin, are you sure your tuning is 15.4 hz? I'm not trying to say its not so please dont take any offence to it. I was just curious because I have the same driver in a 270liter sono with a 6" by 25" port & about 50 oz of fill & it is supposed to have around a 17hz tune.
     
  8. Robin Smith

    Robin Smith Stunt Coordinator

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    Joe,

    Here are the specs from the Adire program, (based on a Tempest, to which the Dayton is similar)

    Volume: 214l
    Fill: 10%
    Port Length: 37.9 cm
    Min Dia: 10.2 cm
    Flare Radius: Inf
    Min Area 81.7 cm2
    Res Freq: 15.4 Hz
    Number of vents: 1

    This is where I modelled my sub. For the 15.4 tuning with my 4" port it gave me 214L, so that's what I made it.

    If I model your numbers it says a tuning of 16.2 with 10% fill. So it looks like both my and your numbers are right.

    How do you calculate weight of fill to percentage of fill. What weight of fill would 10% of a 214L box be? Cos I didn't add that much.

    Thanks


    Robin
     
  9. Jon Torres

    Jon Torres Second Unit

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    Robin, so you just went w/ the tempest driver on lspcad?
     
  10. Robin Smith

    Robin Smith Stunt Coordinator

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    Yep, it was the closest I could get using free and complete software.

    I think I asked on this board and most people said the differences weren't that huge, so the modelling in LspCAD wouldn't be that off.

    Robin
     

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