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Another idea on ohage/cabs/speakers... (this ones a bit crazy though)

Discussion in 'Amps and Cabs [BG]' started by addylewis, Aug 24, 2005.


  1. Say I had the 2 Kustom 4x10s (1200 watts at 2 ohms, but a 4 ohm load)

    WHAT IF (to get the full power out of them) I GET A DEAD 4 OHM SPEAKER (or one thats on its way out) AND WIRE IT UP WITH THEM TO CHANGE THE OHMAGE (i was thinking of a small hi fi speaker that I could sabbotage to disable any sound from it)

    How about that?
     
  2. 'Twould seem to me that if you "sabbotaged" a speaker so that it doesn't sound, you'd effectively be opening the voice coil thus increasing it's impedance to something WAY above 4 ohms and defeating your purpose. Better to get a high wattage resistor and put it in line to affect the overall impedance...
     
  3. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    What the heck for? Really?

    -Ray
     
  4. I'm guessing to drop the impedance to 2 ohms to get the most power out of the amp BUT if you do this, you won't be sending any more power to the "live" speakers. The extra power be disapated across the "dummy" impedance so it's really pointless...
     
  5. Passinwind

    Passinwind I Know Nothing Supporting Member

    There's just no free lunch. Get over it and enjoy what you have. :cool:
     
  6. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    While I'm certainly no expert in electricity or electronics, my limited experience tells me that this just wouldn't work (at least not to get the results you want).

    I assume you want to take two 4 ohm cabinets and somehow get them together to present a 4 ohm load to your amplifier.

    Let's roll with your theory...

    You have both cabinets wired together in parallel so together they present a 2 ohm load to your amp. So add two "dead" speakers (presumably 4 ohms each, wired to each other also in parallel to create a 2 ohm load) , and wire them in series to the two cabinets so (in theory) the end result is a 4 ohm load presented to the amp. So far, so good.

    First problem. If the speakers are indeed "dead", they are no longer converting the energy from the amp into sound, instead something else has to happen to that energy... Excessive heat dissipation, Voice coil melting, etc. In any case, sooner or later (I'm guessing sooner), when the speaker blows (or burns, or melts) the load being presented back to the amp will no longer be 4 ohms and you'll be back to square one with the two cabs taking all of the energy from the amp, but also presenting the original 2 ohm load to that amp.

    Second problem. Let's assume my first theory is wrong and the amp will continue to see a 4 ohm load and will not be damaged. So all of the wattage from the amp is being distributed among the two cabinets (8 speakers) and the other two "dead" speakers. The "dead" speakers would be soaking up a percentage of your power, but not converting it to sound (since they're "dead", right?), so while you'd get more power out of your amp, not all of it would be going to the good speakers.

    - Ugly.
     
  7. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Yeah, my post was mostly to get him to think these things:
    1) lowering the impedence at BEST will get you 50% more wattage, which translate into what, 2dB gain? Not worth the time!
    2) pushing your amp harder for said gains
    3) having a "dead" speaker there can do all sorts of stupid stuff, lets not try it.

    -Ray :p
     
  8. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Exactly...

    Any passive element (resistor, dead speaker, toaster, etc.) that you use in an attempt to adjust the load impedance is going to consume power and REDUCE the amount of power to your speakers...

    If you must have a 2 ohm load, hire a transformer company to build you a 1200 watt, 4 ohm to 2 ohm audio-autotransformer. Then, along with your amp and two 4x10s, you could carry a 100 lb. impedance matching transformer along with you.

    or...

    Go to Office Max, buy a Sharpie, cross out the 8 ohm rating on the label near the cabinet's input jacks and write in 4 ohms. Then, every time you worry about it, look at the back of your cabinets and remind yourself that they're 4 ohm cabinets and you're running your amp at 2 ohms.

    As I wrote in another thread...unless your amp puts out more than double its 4 ohm power at 2 ohms, running it at 2 ohms won't be louder...

    Besides...if you don't run the amp full blast all the time, you're not using anything near full power anyway...
     
  9. ok, cheers for the advice (I'd just like a way to get the full 1200 watts out of 2 600 watt 8 ohm cabs without re-wiring them - you can understand my theory though can't ya?) :bassist:
     
  10. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Yes, but you're not going to gain anything other than music masturbation of getting "more" for "nothing". Only way you'd even notice is if you got more cabs...

    -Ray
     
  11. uglybassplayer

    uglybassplayer

    Aug 24, 2001
    New Jersey
    The best advice I can give you is "Let it go!" I assume you have a GrooveBass head. The 1200 watts is at 5% THD anyway, and 800 watts (at 4 ohms) is MORE than enough to get you though any gig (including outdoors) even without any PA support. If you find yourself needing more power than that out of your stage rig, I sure hope you and the rest of your band mates are wearing good earplugs.

    - Ugly.
     
  12. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The first notion you have to rid yourself of is that watts have more than a cursory relationship with sound levels. They don't. The fact that you keep saying that you want to get watts out of a cabinet points out that you don't know what a watt is. Let go of your watts obsession and read a book or two about audio theory, the knowledge is out there just waiting for you to acquire it.
    One of the first things you'd learn iif you took the required effort is that there is no such thing as ohmage and that about all you'd accomplish with your plan is to start a fire and quite likely blow up your amp.
     
  13. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    There's that darned "ohmage" word again. The term you are looking for is "impedance".
     
  14. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    This would be a completely useless thing to do. Don't get obsessed with maximum watts; they don't mean as much as you think they do.

    You'd get far more benefit from getting more efficient cabs. 800 watts into more efficient cabs will be louder than 1200 into less efficient ones. I speak from experience--I own two of the legendarily inefficient (but great-sounding) Acme cabs. If you can't afford new cabs, you'll just have to work with what you have, which is by no means bad.
     
  15. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Look, let's be honest here. This is the absolute dumbest idea to hit TalkBass in over a week.
     
  16. Say you had a 100 watt light bulb, and wanted to get 200 watts out of the wall. So you put a dummy load in the socket along with the light. Now you're getting 200 watts out of the wall.

    But you're still only getting 100 watts of light from the light bulb.

    That's what you're trying to do here.

    Is the purpose to light the room brighter (or fill it with more sound)? Or is the purpose to just throw an extra 100 watts down the toilet?

    The only thing you can do to get more SOUND out of your amp, is (assuming you have 2 8 ohm cabs now producing a 4 ohm load) is get another 4 ohm cab and run all 3. Then you have a 2 ohm load (a 2 ohm load of devices that turn electrical power into SOUND, instead of HEAT), and you get all 1200 W going toward producing sound.

    Randy
     
  17. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Good analogy!
     
  18. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Doesn't that depend on the ohmage of the light bulb?

    Sorry, I couldn't resist.
     
  19. Hey, if wattage, voltage and apmerage are legit words, why NOT ohmage??

    ;)

    (or maybe impedanceage??)
     
  20. Passinwind

    Passinwind I Know Nothing Supporting Member

    Resistance is futile...