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Using 8" drivers

Discussion in 'Amps and Cabs [BG]' started by m.oreilly, Sep 27, 2010.

  1. m.oreilly


    Jul 5, 2006
    Ukiah, CA
    i have an old mesa 1x15 (ev driver) box sitting in a storage locker, and was thinking of redoing the baffle, and going 4x8" for a small, tight, lighter than my berg box alternate. i was checking out these as the drivers...thoughts?
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    You'll squander the added midrange response of eights by having them in a 4x4 arrangement instead of vertical. As for the low end, the displacement (what really matters) of four Beta 8s is 250cc. That of an average fifteen is 400cc, and a better fifteen as much as 850cc.
  3. rpsands


    Jul 6, 2007
    Phoenix, AZ
    Not to mention that four beta 8s nets a sensitivity of the same as a Kappalite 3015 just about, with half the displacement. And costs more, and weighs more. Yeah. Pretty pointless.

    Also, Beta 8s have such a high Fs that their displacement is not the deciding factor in their effective low end.

    In order to prevent the response from starting to roll off from 200hz you need to tune the cab up around the 60-70hz range, which gives you decent bass response down to the -3db point of 60hz, but response drops like a proverbial stone after that, while excursion does the reverse. Without a steep high pass filter around ~55hz, you are looking at exceeding xmax every time you hit an open note below the A string.

    Bottom line, Beta 8s are not good bass drivers and there are no bass drivers that provide any serious advantage over 10s -- which come in cheaper and lighter. The tiny gains in off-axis response come at huge sacrifices to sensitivity or low end or both.

    Since 10s are decent off-axis to a 2khz crossover frequency, you might as well just cross over to a horn between 2khz and 2500hz.
  4. m.oreilly


    Jul 5, 2006
    Ukiah, CA
    "there are no bass drivers that provide any serious advantage over 10s"
    so those cabs with a bunch of 5" or 6" drivers are...?
  5. Korladis

    Korladis Inactive

    Beaming like crazy, presumably.
  6. rpsands


    Jul 6, 2007
    Phoenix, AZ
    Earning your money through marketing rather than engineering, generally.
  7. rpsands


    Jul 6, 2007
    Phoenix, AZ
    And comb filtering like a boss, since most of those cabs are at least 2 woofers wide if not 4.

    Everyone loves the Henry 8x8 but it's not any louder than a quality 4x10 and beams even worse because the woofers are so far apart--geometry's a biatch like that, but nowhere near as nasty as acoustics.
  8. elavate7


    Jul 8, 2009
    its all about "THE POCKET"
    i have a 4x8 and i love it!!!
  9. 5sicks


    Sep 27, 2010
    Rocket surgeon doesn't know how to link it but look at Phil Jones cabs for the ultimate multi-small driver stuff. Highly praised by some heavy hitters. I never saw one but I don't rule anything out since I heard of resurrection.
  10. m.oreilly


    Jul 5, 2006
    Ukiah, CA
    but they're not 10" drivers!!!
  11. rpsands


    Jul 6, 2007
    Phoenix, AZ
    Yes. And by ultimate, he means you can spend as much for every 5" woofer in your cab as you would for each 10" woofer in an ordinary cab, roughly. Sometimes a little less than that.

    What I can't believe is someone can claim 96db from 35-15khz from 6 5" woofers. That's like saying that the cabinet has better low end extension and comparable sensitivity to an Ampeg 610HLF...and louder and as low as an Acme B4.
  12. 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.

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