Psst... Ready to join TalkBass and start posting, make new friends, sell your gear, and more?  Register your free account in 30 seconds.

Question for cab DIYers!

Discussion in 'Amps and Cabs [BG]' started by Bigwan, Mar 17, 2004.


  1. Bigwan

    Bigwan

    Feb 22, 2002
    Ballymena (hey)
    Just a question for all the speaker builders out there.

    I'm thinking of 2 3 way cabs with an Eminence Kappa 15LF as the bass driver, an eminence 10" driver of some sort for mids and an Eminence APT80 pro tweeter with an eminence 3 way passive x-over to sort it all out. I usually only play 4 string (drop D tuned at times).

    I'm currently using 2 1x15 home made cabs loaded with Kappa 15LF drivers, which sound pretty decent (and will be canabalised to build these new cabs - thanks to bgavin for the measurements! ;) ). I'm just wondering what would be the best midrange driver to match the output of the Kappa LFs I already have...

    Also, does the volume of the enclosure for the midrange driver matter if it won't have to handle anything below 500Hz? Is a sealed enclosure acceptable?

    Cheers

    Ian
     
  2. Add an Eminence B102 10" and use the pxb3:5k0 crossover with the APT-200 driver/horn combination. This one has the longest air column length, and the lowest cutoff frequency.

    This will keep your both woofer and midrange right at 95 SPL at 1 watt. Both will balance with each other, loudness-wise, and will crossover very smoothly at 500 Hz. The APT is much more efficient (louder), so you will have to add an attenuator for the APT.

    The crossover is an internal type, and does not have the attenuator built in. The B102 with its whizzer cone, will hold up fairly well to 5 KHz. I figure this system is good for an honest 200 watts, and will produce about 118 SPL without exceeding Xmax in the 15LF, or over-current in the B102. The APT is only rated around 85 watts, again an attenuator will be needed.

    [ edit ]

    The 15LF is a BB4 type driver, with a higher qts. Knowing these drivers have a hump at Fb then a very rapid rolloff, I would use the BB4 tuning (3.62 cubic feet at 39 Hz), instead of the larger QB3 or Flat alignments. This will put the box right in line with your drop D tuning, and produce the least mud.

    Is this the tuning used in your current 15LF cabs? If so, and you like it, then you know what to expect.

    The B102 will operate very well as a mid-range driver in a sealed subchamber of 0.31 to 0.50 cubic feet. The volume is not critical at all, as the B102 is producing no low bass. I would do 0.31 cubic feet, and stuff it with 0.31 pound of fiber fill to absorb high frequency reflections inside the subchamber.