Build small IB with two low excursion drivers?

Discussion in 'Home Theater Projects' started by PaulDF, Aug 11, 2003.

  1. PaulDF

    PaulDF Second Unit

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    As always I am trying to find ways to improve what I've got. I had an idea and wanted to run it by you all to see just how silly it is!

    I have two old 15" drivers out of some 3-way towers. Their excursion is quite low, and their magnets are quite small as well. What if I mounted them as an IB, and ran perhaps 100 watts to each. I am sorry, I have no specs and I don't believe there were any distinguishing numbers on the magnet or frame.

    Would I get any usable spl out of them? Or would they best compete with some of the crappiest home subs out there?
     
  2. Jeff Meininger

    Jeff Meininger Second Unit

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    I'm not the expert here, but I'd think the best design for a low-excursion sub would be a vented design with a very aggressive rumble filter to handle whatever falls below tuning. To determine the cabinet volume, tuning frequency, and rumble filter settings, you would NEED specs on the driver, though. I betcha the 3-way tower cabinet is probably a pretty good alignment for these drivers, though.

    If you're not using those 3-way towers and just want to fool around with the drivers, then I say give the IB a shot. Just make sure you build your manifold (or whatever) with driver cutouts that will fit a couple of tempests or AV15s. That way, if and when your drivers self-destruct from being bottomed or overdriven you can just drop in a couple of proven sub drivers and be in business.
     
  3. ThomasW

    ThomasW Cinematographer

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    Not a good idea to use drivers that are actually 'woofers' in an IB subwoofer.
     
  4. TimForman

    TimForman Supporting Actor

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    Isobarik may be a good option though. The design tends to bring out the best is less than optimal woofers.
     
  5. PaulDF

    PaulDF Second Unit

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    Thanks guys
    Isobarik did cross my mind at one point, but I don't have a proper amp for it. ThomasW is right, this driver is really only a woofer. I can't see them working very well in an IB. (though it would give me a good excuse to buy another Tempest [​IMG] , if the manifold was already built etc.)
     
  6. Dan Hine

    Dan Hine Screenwriter

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  7. ThomasW

    ThomasW Cinematographer

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    The only advantage to using an isobaric config is that it allows the enclosure size to be cut in half. Other than that it's no different from any other box
     
  8. Jack Gilvey

    Jack Gilvey Producer

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    Never understood the seemingly mystical qualities attributed to isobaric loading. If box size isn't the primary consideration, I've always seen it as a waste of a driver and of wattage.
     
  9. PaulDF

    PaulDF Second Unit

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    Dan - My not proper amp is one per channel of a 100w/ch receiver. I would think both drivers need to receive the exact same signal, and I'm not convinced two separate channels will be exactly identical.
     
  10. Jack Gilvey

    Jack Gilvey Producer

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    People use stereo amps all the time for dual-driver subs, or even a channel feeding each voice coil of DVC drivers...shouldn't be a problem from that perspective.
     
  11. PaulDF

    PaulDF Second Unit

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    Yes, that was how I powered my DVC sub for a while too. But I thought with an isobaric that the two drivers had to be exactly out of phase with each other. Perhaps a slight difference either way from 180 degrees isn't that big of a deal... Doesn't matter, I don't think I'll ever build a clamshell.

    thanks
     

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