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Sub building question

Discussion in 'Home Cinema Building DIY' started by Mylo, Sep 16, 2004.

  1. Mylo

    Mylo
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    Now I need you guys help :D . In my haste to build my sub box I decided not to put in the internal brace board as I am only using a fairly low powered Amp. Cider gives me silly ideas like that :blush: . I now think some sort of bracing is in order, got any ideas? I thought about cutting 4 x 90 degree triangles and just gluing them inside the box to stop the sides resonating, do you think this will work ok? The other option I could think of was to deaden the sides by gluing Bitumin sheeting to the inside faces before I put the acoustic wadding back in.

    The front panel of the box is now 2 laminates of 18mm chipboard & one of 18mm MDF. The back panel is 1 mdf & 1 chipboard. The rest of the box is 18mm chipboard. I used the MDF as the outside as it's easier to get a nice finish.

    Cheers, Mylo :)
     
  2. Mylo

    Mylo
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    come on boys :D , any ideas I finish work in 25 minutes and want to start work on my sub again asap.
     
  3. Mat-Moo

    Mat-Moo
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    Is the box actually together? How about a pic, might help us come up with ideas. You could get some 2"x" timber, cut to length then fit that with screws/glue.
     
  4. Mylo

    Mylo
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    glued & screwed I'm afraid :blush: I actually had it running for a few hours before deciding it may be resonating. If my digi camera works I'll post some piccys this evening.
     
  5. Mat-Moo

    Mat-Moo
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    hmmm, I don't think that triangles will do the job. Depends how big you can make them, the bigger the better I guess.

    Maybe you could do this?
     

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  6. IronGiant

    IronGiant
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    How about a crosspiece with a bolt through the middle? Flatten it, post it though the driver hole, open it out, gluing and screwing in place and then tighten the bolt. Or better yet, something like a noughts and crosses grid.

    Dave
     
  7. rob_w

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    Try a couple bits of plywood say 100mm wide, glue and screw each end to the sides then glue and screw the middle....

    Rob
     

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  8. Mylo

    Mylo
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    Some good ideas there, thanks guys. I discovered last night that cutting a square in half to make 2 triangles is not actually that easy with a circular saw. I've also cut a couple of 150mm wide braces which I'm in the process of rebating to form a cross shape. Going to have a play tonight and decide which of the 2 methods to use :smashin: .
     
  9. Mylo

    Mylo
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    The recycled sub lives at last :clap: Initial sound tests were very good :thumbsup: Will explain more later.
     

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  10. Mylo

    Mylo
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    The design is just a standard cube of 18mm chipboard with the front baffle made of 2 laminates glued together. Once completed I added another 18mm laminate to the front and back but this time using MDF, which was glued and screwed in place. The idea was to not only strengthen the box but also to cover all the joins. The internal bracing was retro fitted as I could feel the sides of the box resonate during early testing. The brace is basically 2 MDF boards rebated so that when put together, inside the cube, they form a cross which was glued and screwed together. Once dry the screws were removed and the holes opened up to approximately 1 inch to allow airflow. The brace was secured in place by drilling through the centre of the 4 sides and then putting a single screw in each one and lots of hot glue on the inside. The inside of the chamber was then fully wadded and the hardware fitted. The speaker is bonded and screwed in place as I don’t intend ever taking it out again. The amp is mounted on a rubber gasket fitted in a rebate. The speaker stands on the spikes from the original donor sub. The sub despite having a low powered amp manages to fill my 3m x 5m room very nicely.

    Donor sub: Gale sub 10 (amp and spikes reused)
    Driver : BK electronics 12inch (donated by Shinobiwan)
    Loads of 18mm chipboard and MDF
    And many, many sticks of Aerospace grade hot glue.
     
  11. Mat-Moo

    Mat-Moo
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    What rating is the amp panel then?
     
  12. Mylo

    Mylo
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    I beleive its only 60 watts rms
     
  13. Mat-Moo

    Mat-Moo
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    I would think that to be more than enough to drive that woofer... I've got another BSB12 here :) about time we did some Iso-Barik stuff!
     

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