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The 2x12 "super bassman" build.

Discussion in 'Amps and Cabs [BG]' started by troyus, Mar 24, 2009.

  1. troyus


    Apr 9, 2008
    San Diego, CA.
    So a few days ago I posted a question about those Fender Bassman cabinets and the response I got was they were not that great...

    I was going to turn my Avatar 2x12 guitar cab into a dual use bass cab, but was told, this is too small. And it did have an open back...

    So, I went to Home Depot and bough meself some 13 ply Birch...

    And after a few hours of cutting, gluing, and staple gunning... I have a big wooden box! Here's a picture of it in progress next to my Avatar guitar 2x12 cab:


    The dimensions of the cab are as follows: 23hx28wx16d

    My question to you cab building types is: Which 12" speakers should I use? And what type of port should I go with?

    It is a closed back design and sealed pretty darn well.
    Any advice, suggestions? It has to work for both guitar AND bass, as an extension for my Fender HRD amp and as the main cab for my Ampeg V4 (bass).
  2. uaudio


    Apr 11, 2008
    I'm no expert, but don't the drivers dictate the box dimensions, not the other way around?
  3. troyus


    Apr 9, 2008
    San Diego, CA.
  4. Mystic Michael

    Mystic Michael Hip No Ties

    Apr 1, 2004
    New York, NY
    It's only 23" high, but 28" wide? So what we're seeing is the cab on its side?

    Seriously, I would build it the other way, so you can stack the drivers vertically within the cab. And no way would I try to build a dual-purpose cab for guitar and bass guitar. You lose too much in the compromise, ending up with a cab that offers passable performance for both guitar and bass guitar, but truly excels in neither one... :meh:

  5. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    yes, there is alot of info on cabinet design out there, but personally, i think that your cab will work very well. i just installed four Eminence Deltalite 2512's in an old Ampeg V4 cab (they are not ported) and the cab sounds awesome. my Ampeg cab's outer dims are 30x26x14 so you have enough cab volume for them. i would glue the baffle board and back on (solid) and front load the speakers (like on the V4), and put bracing from the speaker baffle to the back as well. then just build a removable grill board so you can access the speakers. i would also line the sides and back of the cab with egg crate foam to deaden vibrations.

    IMO, the good thing is that you made the cab alot deeper than a fender cab.

    with my SVT my V4 cab blows away my SVT610HLF and easily sounds as big and full as my SVT 8x10 cab.

    2 cents..........
  6. Thor

    Thor Gold Supporting Member In Memoriam

    You might find that this thread documenting the conversion
    of a 2x12 guitar cab to a 2x12 bass cab to be relevant and
    useful in your project.

    DIY Upgrade of the Rat Shack 2x12 Music Cab to a
    2x12 Ported Bass Speaker Cabinet by Thor

    After doing this build I completely concur with Mystic Michael,
    build a cab to the optimum specs for its particular use.
    The thread is 2 pages, the first of which is devoted to
    technical dicussion and the second is the build itself.
    Many of the issues you will encounter are touched upon here.
  7. Stromrider


    Feb 16, 2008
    CT, USA
    I assumed your measurements were outside dimensions, factored in .75" panel thickness and got 4.78ft^3. I used 4.5ft^3 in WINISD pro to account for bracing, etc.

    Tuned to ~47hz, two Eminence Delta 12LFA will have a -3db point of ~50hz in that box and handle ~200W above 45hz. I don't know how they'd sound for guitar, but this would be a pretty good bass cab with these drivers.

    Use two 4" diameter ports, 4.5" long with flared ends.

    I wouldn't bother with sealed. I don't know of any 12" drivers that will go low enough with enough power handling in that, or any sized sealed box.
  8. Thor

    Thor Gold Supporting Member In Memoriam

    That's what I ended up with as well. The cab kicks
    serious bootay.
  9. troyus


    Apr 9, 2008
    San Diego, CA.
    OK thanks guys... any recommendations on where to buy ports?
  10. Thor

    Thor Gold Supporting Member In Memoriam

    Read my thread. That's there too.
  11. troyus


    Apr 9, 2008
    San Diego, CA.
  12. Thor

    Thor Gold Supporting Member In Memoriam

  13. Stromrider


    Feb 16, 2008
    CT, USA
    Yup, PE should have everything you need. Post pics!!!
  14. troyus


    Apr 9, 2008
    San Diego, CA.
    Hello again. Still moving forward on this project... got most of the interior parts together now... Cab will be for bass and guitar... Went with the Delta Pro 12-A eminence non neo speakers... Paired with my Ampeg V4 or SVT-VR for bass duties, and a Fender HRD or Epi VJ for Guitar duties

    And so the final question is... tweeter or no?
  15. Thor

    Thor Gold Supporting Member In Memoriam

    Where are the PICS? :bawl:
  16. troyus


    Apr 9, 2008
    San Diego, CA.
    Pictures soon! Looking like no tweeter.. and no porting I think... box should be big enough to not need it. And if I do, can always add it later right?
  17. bassman10096


    Jul 30, 2004
    If you want to go with porting, download WinISD or other cab design freeware, enter your speaker parameters and the size of the box you've already built, then tune to frequency and the program will reverse engineer the size and length of the ports you need. I like WinISD because it has a lot of drivers' parameters preloaded (so you just identify the speaker you are using) and it lets you enter the thickness of your plywood along with the exterior dimensions of your box (rather than doing a lot of extra calculation to get the interior volume).

    Sounds like your building techniques are sound (usually the biggest challenge), so you are essentially just trying to tune the cab you already have built. Good luck.
  18. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The Delta Pro 12 works best in a 55 Hz vented cab with 2.5 cu ft net volume per driver. It is totally unsuitable for a sealed cab. You would have been far better off to do adequate research on how speakers and speaker cabinets work before starting your project and choosing your drivers. Too late for that now, but at the least figure out how to make those drivers work as best as can be expected in the cab you built before mounting them.
  19. troyus


    Apr 9, 2008
    San Diego, CA.
    Well I guess the good news is based on my interior dimensions, I hit about 2.475 CU FT per driver!!! How's that for guesswork! :D

    Based on your advice, I will add the port tubes...
  20. troyus


    Apr 9, 2008
    San Diego, CA.
    OK, downloaded WinISD... think I figured it out... a little confused though, earlier, someone mentioned 47 hz, then bill says 55hz... I tune this with the ports... which way should I go??? Primarily it's a bass cab, but I'd love to use it as a guitar cab as well...

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