DIY platform sub - 122dB @ 23Hz

Discussion in 'Archived Threads 2001-2004' started by Dave Milne, Dec 3, 2002.

  1. Dave Milne

    Dave Milne Supporting Actor

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    Edit: Sorry the link didn't work
    I needed a riser for the second row couch so I decided to create a sub. It's about 10 cu ft tuned to 23Hz using a JBL 2245H 18" driver. With 6dB of boost it's ruler-flat to 23Hz . BassBox models it at 121dB with 300 watts (actually it's excursion limited at the very bottom).
    This sub is used only for LFE. I have a smaller front sub with a similar alignment using the 15" version of this driver (2235H).
    The box is 1" MDF with plenty of bracing. I used solid walnut trim because I couldn't figure out any other way to protect all edges. Besides it gives a nice look. I'm guessing it's about 250 lb.
    Riser Sub
     
  2. Juan Castillo

    Juan Castillo Second Unit

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    Holy S*%T !!!! Do you put a couch over that? If so, you sure don't need any bass shakers! No grill or protection?
    Either way, nice riser [​IMG]
     
  3. Jeffrey Noel

    Jeffrey Noel Screenwriter

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    Holy crap! Bet that gives your tushy a nice massage! [​IMG]
    BTW, do cover it up with the couch? I'd be afraid it would get damaged easily.
    Very professional look to the riser also! [​IMG]
     
  4. Dave Milne

    Dave Milne Supporting Actor

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    Yes, it's got a couch over it. And the couch feet are short enough that little hands and/or small objects are not likely to get in and cause damage. I probably should think about a grille, nonetheless...
     
  5. Allen Ross

    Allen Ross Supporting Actor

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    thats really thin, is the magnet sitting on the floor, if not whats the gap
     
  6. Dave Milne

    Dave Milne Supporting Actor

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    Allen,
    The riser is about 9" total height. I arrived at this value through some measurement using the actual chairs and a couple of willing test subjects (myself and wife [​IMG]) As I recall, this fortunately leaves about an inch gap between the magnet and the floor of the box. The driver has a vent at the back of the magnet and I wanted to make sure there was some clearance.
     
  7. Owen Bartley

    Owen Bartley Second Unit

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    What an awesome idea!!! I can't believe I've never seen it before! And yours looks great, nice work.
    Now I'm dreaming about a dual tempest riser... [​IMG]
     
  8. Bryan Michael

    Bryan Michael Supporting Actor

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    how big is that total dinentons and how much mdfb did you use i have my seccond row on a 6 inch platform this is a good idea i have to pull the rear couch away from the wall
     
  9. Miklsan K

    Miklsan K Agent

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    Very cool design Dave! Back when I was in college, I worked at an audio shop. I had a friend that built a couch riser with a pair of twelves. It rocked even back in the Pro-Logic days! I also saw another long thin box with four 10s that was designed to sit behind a couch. It didn't sound very accurate, but it sure made watching Days of Thunder a lot of fun! If you want to see the couch riser taken to the extreme, check this out:
    http://www.royaldevice.com
    I am sure some of you remember this one!
     

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