Help finalize my sonosub plan, please.

Discussion in 'Archived Threads 2001-2004' started by Brett Miles, May 19, 2001.

  1. Brett Miles

    Brett Miles Stunt Coordinator

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    Background:
    I've had a Shiva tucked away for some time now (since the initial HTF deal). It took me some time to find the tube at a reasonable price and then some additional time to actually drive to the place. When all the projects started creeping up, and I was regularly reading this section of the forum, it seems like the only thing that was around for free was WinISD. My initial plans were based on this (and a heavy dose of the Ron S. end table model here http://www.hometheaterhifi.com/volum...tember-99.html ). Now there's this thing on the Adire site that I downloaded, but it really doesn't make a whole lot of sense to me.
    Now then:
    The project finally got underway today. I've got a 26" length of 24" dia. tube cut as well as 4 internal end cap pieces from 3/4" MDF. This leaves 23" of internal tube (10405 in^3). The plan was to have dual 4" (already have the pipe, so please no suggestions for different sizes) ports and a tune around 21hz. If I'm to believe WinISD the ports will have to be 23-24" each for a fairly flat curve -3db around 20hz. I was planning to get the port flares from Madisound (although I'm not sure what exactly these look like from the nonexistent description on the site - do they have a clear inner and outer piece for each set?). SOOOOO . . . what do the experts think about all this, what alterations are necessary in port length for the flares and/or bends in the port structure, and what about stuffing?
    Thanks for the help!
    P.S. I mentioned that I haven't been following this area for some time, and I figured it was easier to give my specific ideas/questions rather than searching endlessly for something that may or may not apply in another thread.
    If someone knows a specific thread that might help, let me know.
     
  2. Chris_Campbell

    Chris_Campbell Stunt Coordinator

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    I don't think it's really necessary to use stuffing, but you may want to use a polyfil batting to line the inside of the tube with. It helps to minimize the standing waves developed between the two endcaps. I just bought a sheet (it's used for making quilts i think) of this stuff at the local craft store, and used some tacky glue (comes in the gold colored plastic bottle) to affix it to the tube. The glue is a little more cost effective than the common velcro method. Good luck.
     
  3. Patrick Sun

    Patrick Sun Studio Mogul

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    You don't need more than 3/4" of endcap on each end, so save a bit of internal volume, and forego the double 3/4" thick internal endcap if you need the extra volume. I have 2 subs built with only 3/4" of endcap on the insides, and they perform fine. Just nail and caulk the perimeter well.
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    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  4. Brett Miles

    Brett Miles Stunt Coordinator

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    I assumed that Madisound sold the flare pieces separately, but I found out otherwise when I called today. Does anyone sell just the flared ends to fit into 4" PVC? Also, does the kit they sell come apart and accomodate a longer length tube, because that isn't going to be long enough?
     
  5. Julian Data

    Julian Data Second Unit

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    Brett,
    Those flared ports come apart so you can add more "length".
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