speaker cabinet tone questions.

Discussion in 'Amps and Cabs [BG]' started by jim primate, Sep 15, 2004.

  1. jim primate

    jim primate bass guitarist.

    if a cab is built solid to typical specs, say 25.5"H X 23.5"W X 18.25"D for a 1x15 cab. how much difference does the speaker make in the tone of the cab?

    and if all else is the same (quality of build, wood, covering, and speaker) what tonal differences would there be if any between a cab of the aforementioned specs and one that is 27"H X 25"W X 16.5"D. where the bigger cab has a smaller port and the smaller cab a bigger port?

    and what kind of difference does the size/placement of the port make?

    thanks in advance.
  2. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    the driver can make a big difference
    cant help ya with the 2nd question
  3. Those dimensions sound familiar.... *googles both dimensions*..... you're talking about a Carvin RL115 vs. an Avatar B15H, aren't you?

  4. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    The speaker makes all the difference in the world. Thiele-Small Parameters such as free-air resonance (Fs), Total Q (Qts) and Equivalent compliance (Vas) when plugged into a program that emulates Thiele & Smalls work to help you predict the low frequency response of a given woofer in a given sized box, tuned to a particular frequency.

    The other thing that you need to consider is the high frequency response of the driver...that too varies all over the place.

    The box volume and tuning frequency must be chosen for each particular speaker. Yes, you'll find that there are a lot of 15s on the market that have similar T-S parameters but the art of loudspeaker design comes into play when you do the final tuning (as the programs get you close, but probably not dead on).

    According to Andy Lewis (of Acme) port placement doesn't make any difference. There are those that disagree. You can read Andy's take on the subject at www.acmebass.com

    There is a mathematical relationship between port cross-sectional area, length and the tuning frequency. Such calculations require the corrections based on whether the port is round or rectangular, etc.

    In all, it's a complex subject for which there really are no easy answers...other than to listen to the different cabinets and choose the one that sounds best to you regardless of what the specs might suggest.
  5. timibud


    Aug 29, 2004
    BillyB nails how much there is to it, but the true beauty of it all is you can always throw a speaker into a cab & decide if you like it or not! ;)