Subwoofer plate amp mounting opinions

Discussion in 'Home Theater Projects' started by JoeFish, Jun 29, 2005.

  1. JoeFish

    JoeFish Stunt Coordinator

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    Hey all. I'm just finishing up a new enclosure for my Shiva III. I had been running it off one of the channels in my Outlaw 7100 amp (160w RMS into a 4 ohm load). I've now decided that I want more oomph, so I've been looking at:

    Parts Express 300-794

    ...which seems a good compromise between price and performance. But since I've already built the box, I really don't want to rebuild the whole thing to sink the plate into it. Has anyone had experience externally mounting their plate amp? I'm thinking it'll look pretty goofy. I could just cut a hole in the side and drop it in, but that'll change the volume of the enclosure, yes?

    The other option is to get a regular component amp, but most that are designed for subwoofers seem to be plates.

    Suggestions are welcome [​IMG]

    -Joe
     
  2. chuckg

    chuckg Supporting Actor

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    Well, here's a couple thoughts:

    Build the plate amp into a separate little cabinet and hide it somewhere out of site. A few feet of heavy speaker wire from the amp to the sub won't hurt anything.

    Add thickness to the wall of the sub cabinet, so the amp is actually external (won't change interior volume) but looks built-in. Warning: may look stupid. Sort of like you tacked an extra box onto the outside of your recently completed speaker cabinet.

    Use a separate plain old amp. If your recever or pre/pro is doing the bass management, then the plate amp and the ordinary amp would be doing the same job. This is what I have since the plate amp on my JBL PB12 went goofy.
     
  3. Dave Poehlman

    Dave Poehlman Producer

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    Going by the cutout dimensions (9" X 9.25"), and assuming you have .75" thickness to your enclosure... it'd use up about 145 cubic inches to your enclosure which is just over 2 liters. It's hard to say for sure until you actually have the amp in hand.. but I'm basing this off the dimensions in the description and figuring the heatsinks take up about .5" of the depth (they're probably more).

    2 liters is pretty negligible if you're dealing with a large enclosure.
     
  4. JoeFish

    JoeFish Stunt Coordinator

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    I'm so glad to hear that [​IMG] It's the 142.5l EBS enclosure, so I think I can give up a couple of liters. 2 liters is only 1.4% of the volume. I'll prolly shim it up with a layer of MDF to minimize the impact.

    Thanks!

    -Joe
     
  5. JoeFish

    JoeFish Stunt Coordinator

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    Actually, there's a misprint on their website. It should be 4 1/4" deep, not 3 1/4". So assuming 1/2" for heatsinks and 3/4" for MDF, that's 4.1 liters of displacement. Will that still be negligible in a 142.5l enclosure? If I add a 3/4" spacer that drops the displacement to 3 liters.

    Thanks,

    -Joe
     
  6. Dave Poehlman

    Dave Poehlman Producer

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    You may lose 1 or 2 dB in your bass extension, but I doubt you'd be able to hear any difference.
     
  7. JoeFish

    JoeFish Stunt Coordinator

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    Cool, thanks. That's one less thing to worry about [​IMG] Would adding a bit of polyfill help "make up" for the lost space, or should I just forget it? I'm not worried about max SPL, I just want it to sound good and play low.

    Thanks,

    -Joe
     
  8. Dave Poehlman

    Dave Poehlman Producer

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    Yes, stuffing can help even in ported enclosures. I'd say about 5 lbs of fill would do the trick. Just make sure it's not obstructing the driver or the port.

    Keep us posted on how things turn out.
     
  9. JoeFish

    JoeFish Stunt Coordinator

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    Thanks, I will. Once the PE stuff gets here I'll start a new thread with some pictures and SPL measurements.

    Incidentally, here's some pix of the sub that this one is replacing:

    http://www.gotmaille.com/sub/

    -Joe
     

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