Reduce sealed cab volume with e.g. styrofoam blocks? Listen for what?

Discussion in 'Amps and Cabs [BG]' started by LetItGrowTone, Jun 25, 2019.

  1. LetItGrowTone

    LetItGrowTone Gold Supporting Member

    Apr 2, 2019
    As cabinet volume decreases the low bass will decrease but should tighten up, and if the volume goes too low a peak (sounding boxy) will appear.
    Is that right?

    Styrofoam is closed cell. Suggest a different lightweight material?

    Ok, I'll tell the whole story:
    I'm using a low powered tube amp and that won't change for now. I understand that the low damping factor loosens the low bass, and combined with a ported cabinet I couldn't stand it, so I blocked the ports and I think it sounds better.
    But I've read that - provided the driver is suitable for both sealed and ported cabinets - a sealed cabinet should be smaller than a ported one for that driver, and the Eminence suggested cab sizes seem to confirm that.

    I don't know the exact model of the speaker, but at least one person on this forum said it's closest to the Delta 15lfa: "This comes from my direct asking to Eminence".
    If that's the case, then it takes a 3-5.9ft3 ported (my box is 3.25ft3), or 1.3-1.5ft3 sealed, according to Eminence.

    Just wondering the audible consequences of using a sealed box 2x bigger than Eminence recommends.
  2. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
    A sealed box that's larger than ideal doesn't sound all that much different, it's just larger than you need to be carrying around. However, don't assume that the recommended box size is ideal. It's usually smaller, because smaller sells. For instance, the ideal size sealed cab for the Delta 15LF is 14 cu ft. The ideal ported size is 28 cu ft. If you had one in a 3.25 cu ft ported cab it would have had a huge midbass hump, making it sound really boomy. Sealing the ports fixes that, but making the cab volume even smaller wouldn't make it better, it would probably make it worse.
    The low damping factor of a tube amp doesn't 'loosen' low bass. The high damping factor of SS doesn't tighten it either.