Which big cab would you build?

Discussion in 'Amps and Cabs [BG]' started by astack, Dec 5, 2016.

  1. 4x12PR300 - A

    2 vote(s)
  2. 4x12PR300 - B

    2 vote(s)
  3. 2xDelta Pro 15A

    2 vote(s)
  4. 2x15PR400

    7 vote(s)
Multiple votes are allowed.
  1. astack


    Nov 12, 2011
    St. Louis, MO
    Itching to build a bigger cab this winter, but can't decide which direction to go, so I thought I'd ask the TB hive mind.

    This cab would be for a rock setting, sometimes in drop C territory. P and J basses with various amounts of dirt, etc. Looking for a single-schlep, 4 ohm, 50 lbs or under ideally, tall cab that can hang with a hard hitting drummer. It'd be nice to have a bit of sound spread to the side for drummer monitoring. Must fit in a standard sedan. Would use 1/2" ply w/ bracing, etc. Cost isn't a huge deal (buy once, cry once).

    Looking at the following formats:
    4 x 12PR300, sealed
    2 x Delta Pro 15A, sealed
    2 x 15PR400, ported

    Obviously the ported 2 x 15PR400 could crush the others volume and low en, and maybe that's the no-brainer. But a compact, 2 x Bag End-esque or 4x12 tower have their own appeal and should still meet my SPL requirements.

    2016-12-05 17_33_52-Untitled - SketchUp.png
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    2016-12-05 17_47_49-WinISD
  2. FingerDub

    FingerDub Inactive

    Jan 8, 2016
    Subbed. Can't wait to see what you make.
    10cc likes this.
  3. Hamish MacCleod

    Hamish MacCleod Supporting Member

    Jul 13, 2014
    South America
    Voted for 4 x 12PR300A... because I'd like to know how it performs, I'm using 2x212's now.
  4. basscooker

    basscooker Commercial User

    Apr 11, 2010
    Northern KY
    Cab fan, hobbyist

    If the graphic is to scale, the 412 looks a bit small, but if it works I'll eat that sentence. Good luck, I'm anticipating a killer cab.
  5. Heck it's hard to decide which one would be the coolest.

    One question: In looking at the 4x12 vertical, all facing forward and comparing it to the 3 verticals with one side firing.
    Do you really get the same SPL with both cabs?

    The side firing cab does not have all four speakers acoustically coupling in the same way as the vertical 4.
    For instance if you had a pair of 1x12 cabs and stacked them or set them side by side you get the extra SPL because they couple acoustically with each other. If you seperated the two cabs by a significant distance, there would be little to no coupling and and little to no SPL gain.
    It seems that the side firing cab would not fully couple with the other three and you get less SPL from coupling gain.
    Just wonderin'
  6. DukeLeJeune

    DukeLeJeune rational romantic mystic cynical idealist Gold Supporting Member Commercial User

    Nov 24, 2008
    Princeton, Texas
    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    At low frequencies, yes. At long wavelengths all of the woofers are radiating omnidirectionally, and their physical separation is a small enough fraction of a wavelength that they are effectively in-phase with one another.

    As the wavelengths get shorter, we transition from having the output of all four woofers out front, to only having the output of three woofers out front (ignoring for the moment the contribution of reverberant energy). So the tonal balance will be a bit warmer than the vertical 412, but in the mids and highs the direct sound will be not quite as loud out front.

    But the midrange and high frequency energy of that side-firing woofer is not totally lost. It obviously will be helping out the tonal balance to one side quite a bit, but assuming a semi-reverberant space, it will also make a small contribution to the reverberant field throughout the room.

    So at midrange and high frequencies you get the same amount of acoustic energy out of both cabs, but because the vertical 412 concentrates that energy more than the 3+1 configuration, you'll get higher sound pressure from the vertical 412.

    By way of analogy, consider a garden hose with an adjustable nozzle. While the same amount of water comes out whether the pattern is wide or narrow, the narrow pattern generates more pressure where it hits.
  7. Stumbo

    Stumbo Guest

    Feb 11, 2008
    I think I'd build two stackable 2x12's with side ports. For me, easier to transport and probably sound fine. I also like the 2x15 Delta pro only with a side port. Maybe two of them.

    When I used to gig it was with 15s. Lately I've used an 8x10 and 8x8 at the rehearsal studio.
    Last edited: Dec 6, 2016
  8. astack


    Nov 12, 2011
    St. Louis, MO
    Yeah it is small -- it's close to 1cf per driver -- but that's the design to get pretty close to the traditional 8x10 FR.
  9. astack


    Nov 12, 2011
    St. Louis, MO
    Yeah, lots of things to like about modular, but I'm leaning toward single schlep. Vertical 2x12 form factor is pretty magical, too.
  10. Korladis

    Korladis Inactive

    I currently use a Sunn 2000S 2x15 with two PR400s.

    Go with the PR400s. Nothing exceeds like excess.
    astack likes this.
  11. astack


    Nov 12, 2011
    St. Louis, MO
    Actually, speaking of Sunn and a pair of 212's, a friend has a pair of Sunn Model 3 PA speakers he never uses, so I might as well try the 12PR300's in those first. :cool: They're about 2.2 cf net and sealed, so would be perfect.

    They look like this:

    2016-12-06 14_03_51-Sunn 2x12 Vintage Cab USED _ Reverb.png