Can someone help me work out the port size please?

Discussion in 'Amps and Cabs [BG]' started by Tom Crofts, Mar 10, 2002.

  1. Tom Crofts

    Tom Crofts

    Mar 15, 2001
    I'm building a bass cab and have worked out all my dimensions and stuff like that but I don't know how to work out the port dimensions... I can't find anything on how to do it and I got SpeakerPro6 and I can't work it out.

    My cabinet is gonna be a 2x15 (celestion Q15-2550, the page with the Thiele Small Parameters is at

    The internal dimensions are 120 high by 58.5 across and 35 deep (all cm). The volume is 245.7 litres.


  2. This driver is optimum in 299 litres, tuned at 38 Hz. It has a -3dB cutoff point of 33 Hz, and a calculated (actual) 1w/1m SPL of 96.6.

    The Xmax of this driver is a puny 2.33 mm, and will over excurse with more than 40 watts input power in the 50 ~ 60 Hz low bass frequencies. This limits the maximum loudness to about 112 SPL. This driver will not accept the full 300 watts input power below 125 Hz, due to over excursion of the cone.

    This is a PA system driver and a waste of your time and money for a bass rig. IMO.

    If you want to haul around a huge cabinet, stick a JBL 2245 into it, and get some serious (read: loud) performance and low bass response.

    [ edit ]

    I just noticed you are going to use a 2x15. This doubles the required cabinet volume from 299 litres to 598 litres, or 21 cubic feet.

  3. Tom Crofts

    Tom Crofts

    Mar 15, 2001
    Are you sure it'll suck? Dr. Decibel recommended it to me over the bass loudspeakers... He's been really helpful so far and has helped my tech project to progress much quicker than it otherwise would have... Why would he recommend such a crap driver?

    Thanks for the heads up...
  4. leper


    Jun 21, 2001
    its not a crap driver, just not at all suited to bass guitar
  5. It's a PA driver. Found it on the Pro Sound section of the Celstion site.

    I just run the numbers, and reported what came back. Doesn't look suitable for electric bass at all, to me.
  6. I agree with bgavin. Don't do it, unless you like the sound of farting cones.
  7. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

    Sep 17, 2021

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.