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Which 12" Replacement?

Discussion in 'Amps and Cabs [BG]' started by PhatBasstard, Sep 20, 2005.


  1. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    I'm probably going to be replacing both the 12s in an older, heavily modified Tech Soundsystems (forerunner and similar in design to a Schroeder 1212) cab. The speakers still work fine, but I've used them hard and they are starting to breakup a bit. Plus I've recently discovered the Techs are 4 ohm speakers and had been wired parallel (2 ohm load) which isn't optimum for a crossover that wants to see a 4 ohm load (I switch them to series as the crossover is handling the 8 ohm load better).


    So....opinions: Which 12s would you suggest? (PS. Must be 8 ohm so I can get a 4 ohm load in parallel).
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The drivers must be matched to the cabinet, so without very specific details a recommendation isn't possible.
     
  3. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Wired for 2 ohms? My guess is was supposed to be an 8 ohm cab but someone who didn't know what they were doing has been playing with the wiring.

    Can you give us some details about the cab's dimensions? Does it have an angled speaker? If so, uou might have to calculate the internal volume for us.

    We'll also need details of the porting, namely the number of ports, their width (or diameter if they're round), length and depth.
     
  4. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    Yes, it has the angled speaker and is designed and ported just like the Schroeder.

    The outer dimensions are 22" wide x 14.5" high x 16" deep. The walls of the cab with the outer covering and the rubberized coating I sprayed onto the inside (kind of like the truck bed liner stuff) are about a full inch thick. So I guess the internal volume would actually be about 20" x 12.5 x 13" (deep, 1" for the back and 1" for the front and 1" that the front is back from the front edge). 3,250 cubic inches???....give or take?

    PS. You may be right about the cab being wired wrong as I don't know what the ohm rating was on the original crossover. The one I have now is rated for 4, so If I get two 8 ohms drivers I'll re-wire the speakers in parallel for the 4 ohms.
     
  5. mmm.. i would not be surprised if normall bassreflex tuning does not apply to Tech cabs. They could well be bandpass enclosures with a flared port. This would certainly limit your choice in replacement drivers.
     
  6. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    Essentually, the angled partition (that the angled driver is mounted to) is not connected to the back wall (just front, top, & bottom). There is about a half inch gap the whole length (top to bottom) with an additional triangular cut/port in the corners that is about 2-3" at their apex.

    From what I gathered from the Schroeder thread, they are ported in the same way.
     

    Attached Files:

  7. And both drivers are in the same chamber? or are there 2 chambers?
     
  8. Well, if both drivers are in the same chamber than this would be a bassreflex cab with a flared/tapered port. This means the port acts both as a bassreflex port and as a midbass (rearloaded) horn. This would also explain the midbass 'hump' the Schroeder cabinets seem to have. I guess normal BR tuning should work then..
     
  9. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    Yes, same chamber. And yes, it does have the "mid-bass hump" that Schroeder users have described.

    It's actually a little smaller overall than the Schroeder 1212. If I were to put a couple neo drivers in it, it would be the ultimate portable/big sound cab. Everybody I gig with was absolutely stunned at the power vs. size of this cab when I first got it a few years ago.
     
  10. tadrex

    tadrex

    Mar 25, 2004
    Wisconsin
    Great thread! I've been thinking of replacing my speakers also. I have a Tech CT-4000 which has 4 12's in it. It's rated at 800 watts into 8ohms. I would think that any suggestions for the 2 12 would work for me also. Thanks.
     
  11. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    Yes it should as the CT4000 is simply double of a CT2000 (my cab). I almost picked up a CT4000 (used, ebay) about a year ago, but changed my mind as I thought it would be overkill for anything I do. I had a second CT2000 for awhile but sold it as I almost never needed more than one at a time. :D
     
  12. Well, neo drivers are no holy grail... maybe some normal magnet drivers perform better in this enclosure than neo drivers, maybe not...
    And there might be some new technologies coming that will outperform tech/schroeder: tapped horns for instance.
    [​IMG]
    http://www.danleysoundlabs.com/index.html

    (the picture shows a PA subwoofer, but this technology could also be implemented in a bass guitar cab)

    What make/type was the driver that came out of the tech cab?
     
  13. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    Don't know. The only identifying marking is the "Tech" printed on the dust cover of the cone.
     

    Attached Files:

  14. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    There are some Celestion BX 12's on ebay fairly cheap. Anyone had experience with these?
     
  15. I would try the Eminence Omega pro drivers. They are designed for small enclosures.
     
  16. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Which ones? The BX12-2560, BX12-3075, or BX12-4085. I went looking for T/S parameters on the net and found there's more than one type.

    While we're talking Eminence, wasn't there a thread where it the Delta 12's are possibly used in the Schroeders. In typical mythbuster's style, I think we decided it was plausible.
     
  17. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    Not sure. The ones on ebay say "Jay 5130" on the magnets. I found a site selling them and besides being 8 ohm they say they're rated at 600 watts RMS.
     
  18. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    That's the 4085. It likes a small enclosure but it's -3dB at 120Hz. To me that's better suited for a PA driver, and it'll need subs to to the low work. Not good for Bass unfortunately.
     
  19. PhatBasstard

    PhatBasstard Spector Dissector Supporting Member

    Feb 3, 2002
    Las Vegas, NV.
    OK. So if I stumble on anymore, which of those three (the other two actually) Celestions would work for me best?

    Thanks.
     
  20. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    I'm not sure. I could find references to the other two models, but no T/S parameters. Without those, I'd just be guessing.

    If you stumble on to any more, ask for the T/s specs.