4-way univeral active crossover and power amplifier setup

Discussion in 'DIY Speakers and Subwoofers' started by BillWaslo, Sep 29, 2012.

  1. BillWaslo

    BillWaslo Well-Known Member

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    I've spent the weekend putting this stuff together to make active crossing over easy. Each box has one input, 4 outputs, using the 2x4 MiniDSP kit, and a 4x100W Sure Class D amplifier with the Meanwell 24V 14A power supply. (Of course this doesn't really do 100W per channel at tolerable distortion, but with the Meanwell turned up to 28V, 70W into 4 ohms should be doable and would give >140W for the 4 woofers (driven in pairs) in each Synergy horn!).

    The MiniDSP is powered by a "linear" 12VDC wall-wart supply, since I have lots of those around and they give nice quiet operation and complete isolation from the AC lines.

    Here are the boards (assembled with feline help onto some 3/8" plywood)-
    [​IMG]
    Here they are after they were put inside some oak ply boxes made to make them unobtrusive (the classic "block of wood" look).
    [​IMG]
    I haven't used them yet, other than checking to see that the amplifiers seem to come up ok and the MiniDSP led flashes. I have to rewire the Synergy cabinets so I can bring out all the driver wires while still allowing for use with the passive crossover I came up with (and which I'm actually quite satisfied with... but the DSP crossover should be fun to play with still, and should give a flatter response -- more square waves to come!).
     
  2. Matt Grant

    Matt Grant Administrator

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    :eek:
    I like that, those are almost a perfect match for each other.
     
  3. maxmercy

    maxmercy Just joined the party

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    Terrific idea!


    JSS
     
  4. JackNC

    JackNC Just joined the party

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    I thought of the same thing but I only have one woofer on each side. But I do use the 2 channel version of that amp in my test setup and the sound is fine. It got loud enough driving a single 8 ohm JBL2214 but didn't have the headroom I wanted. No pops, clicks, etc. turning on or off either.
    Nice job on the box.
     
  5. BillWaslo

    BillWaslo Well-Known Member

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    Thanks.

    Still yet to be tried out, haven't had a chance to do the speakers yet.
     
  6. JackNC

    JackNC Just joined the party

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    too bad we can't get midwoofers with dual 4ohm voice coils. Then use the 6x100W board, dual woofers, and have plenty of headroom
     
  7. BillWaslo

    BillWaslo Well-Known Member

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    I have these working on the coSynes, sound really nice. A problem, though, is there's a turn on/ turn off noise that gets rather loud when paired with waveguide sensitivity! I don't think it will hurt anything (hasn't yet, anyway) but I worry about the tweeter driver a little. For now, I just leave it on all the time.
     

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