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BSC, Baffle Width and Inductor Advice Please

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  • BSC, Baffle Width and Inductor Advice Please

    Hello from Australia

    I'd like to re-purpose some old cabinets with new drivers and new crossovers. The volume and port size seem OK.

    However, the baffles on the old cabinets are 8.5" wide and the project for which the new crossover was designed has a 10.7" baffle. The specified woofer inductor for the new project is 1.5mH.

    I'm assuming that approx. 2" in baffle width will be significant and that a larger inductor, maybe 2mH, would be necessary to maintain the amount of BSC in the new design?

    There doesn't seem to be much difference to the drivers' FR and impedance in the Xsim model between the 1.5 and 2mH (graphs att.) The first is with the 1.5mH. Anything larger than 2.0 really mucks up the model.

    Thank you very much for any advice!

    Geoff Click image for larger version  Name:	FR1 with 1.5mH.jpg Views:	0 Size:	84.8 KB ID:	1469808 Click image for larger version  Name:	FR2 with 2mH.jpg Views:	0 Size:	84.1 KB ID:	1469809

  • #2
    As sensitivity and impedance will be a bit different between the two sets of parts, prediction and simulation are difficult.

    Best go with the 1.5 and see, wouldn't be more than a decibel different total compensation. Or the 2 and unwind to check changes.
    One change at a time, and we get somewhere- but we need a stage zero to vary from.

    Comment


    • Geoff Millar
      Geoff Millar commented
      Editing a comment
      Thanks David, that makes sense. The 2mH results in a larger impedance peak at about 1500Hz.

      Cheers

      Geoff

  • #3
    (Not knowing the driver/design particulars) you can create both baffles in Tolvan's "Edge" (free software) and SEE what happens w/a 2" change in baffle width.
    The narrower baffle LOOKs to be "smoother". A dip near 2k isn't as deep (by about 1 dB) and a hump around 900Hz isn't as pronounced (by about 1 dB).

    Comment


    • Geoff Millar
      Geoff Millar commented
      Editing a comment
      Thanks Chris, I'll give that a try.

      The woofer is a Dayton RS180P, the cabinet was made for a DC160 so there will be a little surgery.

      Geoff
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