Tight fit on endcap..how close can components be?

Discussion in 'Archived Threads 2001-2004' started by Seungsoo Hwang, Feb 13, 2001.

  1. Seungsoo Hwang

    Seungsoo Hwang Stunt Coordinator

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    I am making my new sonosub out of 18" sonotube. I am using the Shiva driver and two 4" ports, non-flared as to make everything fit on the bottom of the endcap... The driver cutout for the shiva is 11"d, and Im guessing the 4" ports will be around 4"d. I laid this all out in a cad drawing and it seemed to fit, along with some legs and a terminal cup if it is all tightly squeezed together. My question is how thin can the walls separating the components be? I am doing double endcaps so it will be 1.5" thick. Think it'll work? Anyone else squeeze stuff together like this and made it work?
    thanks
     
  2. Eric M L

    Eric M L Extra

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    Good question Seungsoo! Sounds like we have similar designs in mind. I'm not going to be building mine for a few months yet, but I'm definitely looking forward to updates from you on your construction (and how it sounds).
    How big's your sub gonna be? How low are you tuning it?
    Sorry I can't answer your question. Could you answer mine? [​IMG]
     
  3. Seungsoo Hwang

    Seungsoo Hwang Stunt Coordinator

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    Due to avaliablity of sonotube diameters, Ive pretty much settled on this:
    (1)shiva driver
    (2)4" ports @ 17.3" long
    Enclosure volume ~4.5, tuned to 27hz.
    It looks to be around almost a 18"D x 36"L tube to get the right enclosure volume with endcaps, driver, port etc.. subtracted.
     
  4. Eric M L

    Eric M L Extra

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    Cool! Sounds like a very nice music sub. Oughta work pretty well for HT as well.
    This is what I'm looking at:
    1 Shiva driver (Powered by the AVA 250 plate amp)
    18" sonotube (about 45" long)
    5.8 ft^3
    2 4" ports, 23.5" long
    Should give me a tuning of about 19 Hz
    Definitely keep us updated on the progress you make!
     
  5. Scott M

    Scott M Agent

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    I'm curious why you are both using 2 ports instead of 1. I'm considering a sub of similar proprotions:
    shiva based
    ~5.0 ft^3
    a single 4" port ~14" long tuned near 18hz
    18 dia tube
    What are the advantages/disadvantages of 2 ports over 1.
    Also please post your results when you are finished. Thanks.
    ------------------
    -scott
     
  6. Patrick Sun

    Patrick Sun Moderator
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    Scott, mainly it's a matter of port compression. You'll reach a point where no matter how much more power you input to the driver's voice coils, you won't get anymore SPL out of the sub. Now determining where that point is is left for an exercise of the reader. [​IMG] It's a trade-off. The more port area you have, the less you sub will strain at high power input, but you will need a certain amount of "real estate" on the bottom endcap if you wish to keep the porting on the bottom endcap. Otherwise, just port it through the top and go nuts!
    ------------------
    PatCave ; HT Pix ; Gear ; Sunosub I + III ; DVDs ; LDs
     
  7. Greg Monfort

    Greg Monfort Supporting Actor

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    >My question is how thin can the walls separating the components be? I am doing double endcaps so it will be 1.5" thick. Think it'll work? Anyone else squeeze stuff together like this and made it work?
    =====
    If you want decent mechanical efficiency, then there needs to be enough room to brace between openings with at least a 3/4" x 2-1/2" no-void ply, or hardwood strip mounted on edge. If not, then run threaded rods down from the other endcap, locknut them to the baffle, and use the end of them as mounting studs for the driver. Also cut some small diameter, thick walled PVC pipe to whatever the i.d. of the cab is to encase the rods, and act as long compression washers. Now the load bearing is distributed to the entire cab, for a very rigid structure.
    GM
    ------------------
    Loud is beautiful, if it's clean
     
  8. Seungsoo Hwang

    Seungsoo Hwang Stunt Coordinator

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    Wow sounds like a process! I hope the bracing you mention fit..
    Scott, besides what Pat said, my answer is that it is DIY and we must go overboard at all costs [​IMG].
     

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