Help figuring out IDEAL enclosure size, please?

Discussion in 'Archived Threads 2001-2004' started by rodneyH, Mar 27, 2002.

  1. rodneyH

    rodneyH Supporting Actor

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    I have a spare OLD SVS origional driver. (Fs 20.5hz, Qts .38, Qes .39, Qms 6.6, Vas 4.7, Re 3.2). I will admit, I have NO clue what those #' mean, but I have a couple options.

    1. My bro has an old JBL that I might try to put the driver in, it is 2.815 cubic feet and uses a rear port (about 7" long and just under 3" in diameter),

    2. build my own box,

    3. build a sonotub to the exact dimensions as the SVS it came out of. I am hoping it will work with the JBL enclosure and this could be a huge upgrad for my little Bro, but if that won't work, I will do one of the other options.

    Anyone want to help me out?
     
  2. Patrick Sun

    Patrick Sun Moderator
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    This is a guess using WinISD, but with the existing JBL box, you'll end up with a box tuned to around 25Hz, and the F3 also winds up around 25Hz, so it'd be like a SVS 25-31 model, but the port will cause some port noise down low in the 20'sHz range. There might be a slight hump in the 35-55Hz range (which is good for HT use).

    I'm in the same situation, in that I have a box nearly the same size, but I have a wider 4" port and I can extend the port a little bit, but I will most likely also go for the same SVS 25-31 configuration.
     
  3. rodneyH

    rodneyH Supporting Actor

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    the port is very very flared, I don't even know if it is ever really straight, which would probably be better for decreasing the wind noise?
     
  4. Patrick Sun

    Patrick Sun Moderator
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    Yup, flared is better than not flared.
     
  5. Ron Shaw

    Ron Shaw Stunt Coordinator

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    Using your numbers, the max flat alignment is 3.54 ft3 usable tuned to 22.3Hz, for an F3 of about 23 Hz. Using the box you describe will give you an F3 in the higher 20's with about a 1db peak. Difficult to really predict without knowing the final usable displacement (after subtracting driver, port, etc. from internal volume).
     
  6. rodneyH

    rodneyH Supporting Actor

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    Jack, that is the delema, I have the box, and it is currently being used, I tried to put the other driver in it, but the basket is slightly larger on hte SVS, so I would have to do some modifications to the JBL box, I wanted to check with the knowledgable people here before I really got into it amd ruined a box for NO reason. I am starting to think that it would be better than the fly weight JBL driver currently in there.. Also the thing has hardly any insolation , so I willl add that as well??
     

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