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DIY 2x18?

Discussion in 'Amps and Cabs [BG]' started by Pullman?, Jul 17, 2012.

  1. Hey guys, I recently got a pair of old JBL 18" speakers, had them reconed, and am currently looking for your help. I don't know much about cab construction but I'm determined to build one for these beasts. So the question is, how do I make a 2x18 bass cab?
  2. will33


    May 22, 2006
    Take down the model numbers, etc. and dig up a datasheet for them. Should be available from JBL, or archived/posted by some other speaker enthusiast out there.

    That's step 1.
  3. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    I'd make 2 1x18s. W horns would be retro cool, but no idea if the speakers would be suited. Might not even matter, stick speakers in a W horn, sounds like a W horn. Oldschool.
  4. will33


    May 22, 2006

    Curious as to how high his might reach. There's 18's, and then there's 18's that are only meant to be subwoofers. You can still get some sort of articulation out of a W horn, if the driver is putting out some sort of mids that can make it around the corner.:)
  5. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    Guessing these jobs are actually old ones. W horns are pretty sort so isn't a massive mid scoop, you can still get some clunk out of them even with a passive eq. Sort of got curious about how much difference a hard shiny coating inside the horn would make.
  6. BogeyBass


    Sep 14, 2010
    18" box needs to be deep as possible.
    you looking at 5 to 8 cubic feet per driver (140 to 230 liters)

    Just look at boxes already designed by JBL for them.
    try to lighten the design if you can by using 1/2 ply instead of 3/4
    to lighten it up. Need fair knowledge of bracing methods
    to make lighter material work.

    Maybe a simple form factor would be a standard 8x10.
    Just make a baffle and 2 compartments for 2x18.
    it would have to be much deeper to get the right airspace
    each compartment would have either 4 round ports per driver.
    or 2 slot ports placed on the sides.

    bracing with 2 slot ports is tricky, round ports would make it easier
  7. rickdog

    rickdog Gold Supporting Member

    Mar 27, 2010
    I have an old K151 in a home-built copy of a Sun 118MH. Always wished I had two of them. :D

    Sounded pretty loud driven with a 100W Marshall. There was a surprising amount of upper midrange, I think the mids reflected off the back of the box.

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