D'Appolito question!

Discussion in 'Archived Threads 2001-2004' started by Jim Robbins, May 18, 2001.

  1. Jim Robbins

    Jim Robbins Stunt Coordinator

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    I am in the planning stages for building a D'Appolito speaker using two 5" drivers. I beleive Joe requires either a 6db or 18db crossover for this alignment, are there any other requirements? ctc distance perhaps? crossover frequency?
     
  2. Patrick Sun

    Patrick Sun Moderator
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    I think Joe D. advocates keeping the CtC distance 1.5 wavelengths of the crossover frequency. I use 1 wavelength for my CtC calculation for the tweeter/midrange.
    CtC=13560/frequency (CtC in inches, frequency in Hz).
    My recent project had me using 2000Hz for a crossover frequency, so my CtC wound up being right about 6.75" (13560/2000).
    If you used 1.5 wavelengths xo's at 2000Hz, you'd get a CtC of 10.125". This would mean your height of the front baffle would be kinda tall, over 26". I think you can get away with using 1 wavelength if you want to keep the front baffle height under 20".
    I thought Joe D. now uses 4th order LR's for MTMs (I could be late on my readings) that he's been using with Focals.
    If you use Madisound drivers (meaning they stock and sell the ones you are using), you can get them to design a LEAP crossover for you for around $60 if you don't have access to measuring equipment and other neat knick-knacks.
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  3. Greg Monfort

    Greg Monfort Supporting Actor

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    1WL of the XO point on centers between each mid and the tweeter. Any combination of XO slopes will work, but a 2nd order L-R All Pass is best for most listening rooms IMO as it reduces unwanted reflections while maintaining an on-axis polar response.
    GM
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