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Critique my crazy cab ideas

Discussion in 'Amps and Cabs [BG]' started by Jim Nazium, Apr 9, 2009.

  1. Years ago, I had a Trace Elliot combo amp called the BLX-130 (there was also a lower-powered version called the BLX-80). It had a single 10" speaker in a band-pass enclosure, meaning the speaker was house in a ported chamber and fired into a second front chamber, which had a slot port in the front of the cab. I loved the sound, it had such a deep, tight fundamental all the way down to low B.

    They're still occasionally available on the used market, but they're fairly bulky and weigh around 60 pounds (27kg). I'd really like something much lighter.

    So here are my crazy ideas:
    1. Buy one of the combos, remove the amplifier head, saw off the part of the cabinet that houses the head, and replace the driver with a lightweight "neo" driver. Pair it with a micro-head like a Little Mark II.

    2. Find diagrams of the cabinet and have someone build one for me using a neo driver. Any ideas who might do this?

    3. Forget about it. What's gone is gone.
  2. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    Honestly, I think either idea is good. I'm not sure where you would find a diagram of the speaker. But if you did, any cabinet guy should be able to put it together. good luck!
  3. RedLeg

    RedLeg Supporting Member

    Jan 24, 2009
    Kaiserslautern, Germany
    Nov Shmoz Ka Pop?
    why not just start with a car audio bandpass and spare the TE combo?
  4. Hi.

    "Eminence designer" will calculate band-pass cabs too.

    Just my 0.02€
  5. Kenny Allyn

    Kenny Allyn

    Mar 25, 2006
    If you have never seen one they look like THIS

    ;) ... Interesting concept
  6. IanStephenson

    IanStephenson UnRegistered User

    Apr 8, 2006
    Small but GOOD combo's like this are more than the sum of the parts... The porting design is integrally linked to the speaker spec's - that's true for any cab, but for a design like this, even more so. Any other driver in that cab is going to be a disaster.

    Simlarly (though to a lesser/unknown extent), the amp can be tuned to match/make up for some of the limitations of the speaker/cab system. I've got a hartke kickback (similar amp in terms of it's target market), and while it has a speaker out, the manual notes that you probably shouldn't use it. Switching out the amp on a system like that is going to reduce performance.

    Ultimarlty there's no point in starting with the BLX, other than a concept. If you like the concept (and it is a good concept), then if you're replacing the amp and speaker you'll also need to replace the enclosure too - ie you're building a whole new amp.

    As T-Bird says, Emminence Deigner can design a cab for you. I'd find a neo driver, and then design a suitable band-pass ported cab to go with it, and forget trying to adapt or modify anything but the concept.
  7. gregoire1


    Oct 19, 2008
    I almost bought a blx-130 in a pawn shop but someone beat me to it. It was everything you described but felt like you were carrying around 4 cinder blocks! I was going to do the same thing you describe but keep the speaker (and tweeter) just build a new box out of light weight plywood. The original was made of very heavy (and cheap) MDF. I could probably cut the weight almost in half!
    I'm sure the box design was very speaker specific. Replacing the driver with a neo would completely change the cabs performance for the worse! I wouldn't recomend that.
    Instead, consider building a BFM Omni 10.5, with 10 inch neo driver. It is everything you want in a small, light weight, tuned horn with all the guess-work already done! Build it as an airhead so its a combo with the amp integrated into the cab.
  8. Lot of good ideas here, thanks everyone! I was afraid that replacing the driver wouldn't work :( I'll check out the other suggestions though.

    (edit) The BFM 10.5 looks really interesting. That warrants some more research...
  9. gerryjazzman


    Dec 31, 2006
    New Jersey
    If what you like about the sound of the BLX-80 is it's deepness and ability to reproduce the fundamental of a low B, the BFM Omni 10.5 is not going to do it. I built a pair myself, and while they can get fairly loud and have the ability to "cut through", they don't have a lot of bottom (that's not what Bill designed them to do).
  10. VisualShock


    Feb 19, 2008
    North Wales
    Buy a BLX by all means, but don't, whatever you do, modify it!
    In 10-20 years time they will be worth thier weight in gold, in a similar fashion to ampeg...

    Get some designs, go crazy with them! make a copy and then modify it, rather than taking something that is no longer in production and destroying it...
  11. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    A free lunch there is no such thing as, and bandpass enclosures are proof of that. When well engineered, and that's not easy, they can give a fat low end. They do so at the expense of midrange response. That's why most bandpasses are seen used as dedicated subs for hi-fi and autosound, with separate midbasses to handle above 100 Hz. My Omni 12 and Omni 15 cabs use bandpassed woofers, but they're conservatively tuned so that they'll work to 500 Hz, where they cross to an 8" mid. As for getting a good result from a very small, lightweight bandpass, that's not going to happen. The smaller the box the less the bass response, and since bandpass is two boxes in one the total cab size can't end up being compact. Hoffman's Iron Law will not be denied.
  12. 62bass


    Apr 3, 2005
    The Trace BLX is a pretty amazing sounding combo. I have played through them a couple times and would have bought one if not for the weight. I heard a guy playing fairly loud with a blues trio in a local pub recently with the 80 watt model on a Fender 5 string no less. He filled the room.

    It would be tough to modify the cabinet by dropping in a Neo. You'd only save a few pounds of weight and finding a neo that would match that cabinet might be impossible. But, you could design or have designed one tuned for a neo speaker using more light weight materials and probably have something pretty good. It wouldn't be all that cheap though.

    I know there is no such thing as a free lunch, but for some reason that BLX sounds good in real world use. It shouldn't but it does. There's something about the way that cabinet is voiced that works well for my ears. The Trace amp is nothing special but it does the job.

    I can imagine a pair of those bandpass cabinets with neo speakers being driven by the GK MB 500 watt mini monster. It would be worth a shot if you don't mind risking some money.

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