4-way univeral active crossover and power amplifier setup

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

  1. 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)-
    Here they are after they were put inside some oak ply boxes made to make them unobtrusive (the classic "block of wood" look).
    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. :eek:
    I like that, those are almost a perfect match for each other.
  3. Terrific idea!

  4. 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. Thanks.

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