How important is cab volume in a sealed cab?

Discussion in 'Amps and Cabs [BG]' started by jock, Dec 30, 2003.

  1. jock


    Jun 7, 2000
    Stockholm, Sweden
    The replacement driver (Eminence BP102) for the Ampeg SVT810 wants 1.66 sq ft/driver. But the SVT cab is not that big. It can offer only 1.06 sq ft/ driver according to my rough calculations. How will this affect the sound if you should change the drivers in an SVT810 to the BP102´s? :confused:
  2. That pushes the Qtc up to about 0.813 or a solid "bump" in the mid-bass, and faster rolloff.

    Sealed boxes are MUCH more forgiving of volume changes.
  3. Petebass


    Dec 22, 2002
    QLD Australia
    Yep at QTC of 8 or so is not a drastic change. the original cab probably had a Qtc of 7 to start with.

    Have a look at the attached screenshot. I just used a dummy speaker to create a frequency curve with a Qtc of roughly 7 (yellow line). Then I adjusted the box so the Qtc is 8.5 (green line).

    Hope that helps you visualise it.
  4. Jesus this guy is good ^^^
  5. quallabone


    Aug 2, 2003
    Yes he has mastered the art of plugging numbers into WinlSD
  6. jock


    Jun 7, 2000
    Stockholm, Sweden
    You guys rule! Thanks! :bassist:
  7. Jock, you are looking at an F3 around 61 Hz. Don't expect this to have a big bottom, because it will not.

    With an EBP of 80, this driver is marginally more suited for a vented box. The Qts is pretty high, and combined with this EBP, means it has a weak (read: cheap) magnetic motor. The low BL of 10 confirms this.

    The BP102 appears to be about the only publicly available replacement driver for your purpose. If indeed it is a direct replacement for your cab, then it is the best choice, because it will match with the others.