Length of sonosub legs?

Discussion in 'Archived Threads 2001-2004' started by Brian Steeves, Jul 28, 2001.

  1. Brian Steeves

    Brian Steeves Second Unit

    Joined:
    Dec 25, 2000
    Messages:
    320
    Likes Received:
    0
    I am building another sonosub. This one is a dual Shiva in 24" tube. One driver on top and one on the bottom along with the port.
    What I need to know is what should the distance be between the base plate and the bottom end cap? 4"? 6"?
    Maybe Tom V will chime in here?
     
  2. Julian Data

    Julian Data Second Unit

    Joined:
    Oct 5, 1999
    Messages:
    408
    Likes Received:
    0
    absolute minimum IMHO 3"..
    I would prefer 4" or higher.
    ------------------
     
  3. Brian Steeves

    Brian Steeves Second Unit

    Joined:
    Dec 25, 2000
    Messages:
    320
    Likes Received:
    0
    Hey Julian.
    Yeah it really doesn't matter, I just thought Tom had done some tests on that dimension and came up with some more output at a certain height. It may or may not be the same for a sub like this but I just thought I'd ask. My last one, the single Tempest, had a distance of 6".
     
  4. Julian Data

    Julian Data Second Unit

    Joined:
    Oct 5, 1999
    Messages:
    408
    Likes Received:
    0
    I think it was 2" when he did the tests..
    ------------------
     
  5. Rick P.

    Rick P. Stunt Coordinator

    Joined:
    Mar 2, 1999
    Messages:
    63
    Likes Received:
    0
    My legs are 2.25" and they're a bit too short, as Tom said they would be. As I recall, his 'magic number' was just under 3". You could probably go a bit lower if you use wide flared ports, but my ports (2x4") just use a 3/4" rounded routered edge.
    I have played with my height a bit and found that low-end output improves by 3 or 4 dB until my subs are about 4" off the floor. Above that there is no change in the output.
    BTW, how big of a port are you planning on using with dual drivers?
    Rick
    ------------------
     
  6. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Found what Dr. Hyre wrote to me in my email archive. This is in regards to a Tempest.
    -----
    For max performance, we recommend at least 3x cone area
    in clearance under the sub driver (~4"), and at least one
    vent diameter clearance from the wall, more on both if
    possible.
    -----
    -----
    (PI*D*H) = 3 * (PI*R*R) gives H=3.75" between floor &
    driver.
    -----
    So the height for a Shiva would be around 3". But if you are using a 4" port than it should be at least 4" is how I interpret it.
     
  7. Julian Data

    Julian Data Second Unit

    Joined:
    Oct 5, 1999
    Messages:
    408
    Likes Received:
    0
    That sounds like more the minimum port diameter than anything else, IMHO.
    ------------------
     
  8. Brian Steeves

    Brian Steeves Second Unit

    Joined:
    Dec 25, 2000
    Messages:
    320
    Likes Received:
    0
    Hey Guys, thanks for the responses.
    This sub is more or less a Mike Knapp "Water Heater" clone. Although mine has beefier end caps and internal bracing.
    So the port being used is 8" PVC (down firing).
     
  9. Kyle Richardson

    Kyle Richardson Screenwriter

    Joined:
    Jan 1, 1998
    Messages:
    1,073
    Likes Received:
    0
    I believe my Shiva sonosub had 4" legs while my Tempest has 6" legs. I don't know if they are the correct lengths but they seem to work well. [​IMG]
    ------------------AOL Instant Messenger Name: kyler70
     

Share This Page