Amp to Cab relations

Discussion in 'Amps and Cabs [BG]' started by JacksonsMen, Oct 21, 2006.

  1. ok, so with the SWR 8x8 ive got im looking at [email protected] load. my question is (and i cant seem to find a straigh answer):

    Do i want to have twice as much power in the amp as the cab can take (RMS to RMS) or do i want to match it relatively closely like a 500w RMS head to the 480w RMS know what im saying.... any thoughts
  2. Jiggybass


    Nov 15, 2005
    Sudbury, Canada
    I run even, 200 to a 200 watt cab, But I feel safe running a 600 watt head through it, just as long as you don't overdrive the speakers, you are fine. Better to have more headroom than not. clipping an amp because you have to crank it can do much worse things to speakers. more power = more headroom = less chance of clipping.
  3. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    Just use an amp that's powerful enough to get as loud as you need. If an amp that is rated at twice the power rating of your cab is not loud enough, then you need more speakers.

  4. Bassflute


    Jun 24, 2006
    Endorsing Artist: MTD basses and strings; Bergantino Amps & Cabs
    With bass, more power is better, as long as you're running a clean signal. It's distortion, esp. the wrong type of distortion, that blows speakers; rarely will you blow one if you're running lots of clean power.

    I have run literally thousands of watts into small cabs, and as long as you're not trying to recreate Woodstock you'll be fine. I currently run an Eden WT800B bridged mono into one Bergantino HT112 and it sounds fabulous - that's about 880 watts into a single 12/tweeter cab. At larger gigs, bridged mono, I'll run two Bergs at 4 ohms for a total of a little over 1100 watts. I don't crank it, and if I did I would fully expect them to blow, but it will get devastatingly loud long before there is speaker damage.

    Good luck,
  5. As Alex implies, what you're asking is kinda the wrong question. The real issue is not the amp to cab relation, it's the relation of the power you have to the power you're gonna need to do the kind of gigs you're trying to do. The idea is to get more than enough power for your situation. Which means you don't use it all, which, as Jiggy suggested, is what headroom is. Once you have more than enough power for your playing situation, the amp-cab relation (e.g., 2:1, 1:1, 1:2) is not that important, as long as the cab has enough capacity to handle the proportion of the amp's power that you're using on a regular basis. For example, if your gig requires a 200 W amp, and you buy a 600 W amp, you're likely in good shape regardless of your cab's power handling (within reason!). All else being equal, you don't gain any advantage (assuming, again, that you have more power than you need and aren't using all of it) from using a 300 W cab as opposed to a 600 W cab; you don't gain an ounce of headroom that way, because the amp-cab ratio is irrelevant to amp headroom per se. It just doesn't matter that much.

    There are other factors that go into chooisng a cab, such as efficiency and frequency response, but for simplicity's sake I'm ignoring these for the moment.

    Believe it or not, there's a TON of stuff on this subject in this forum. Search on headroom or power handling.
  6. It's not distortion per se that kills speakers, as has been explained on this forum by people such as Bob Lee and Mark Reccord. It's overexcursion or overpowering.
  7. RWP


    Jul 1, 2006
    Crown engineering on their web site suggests having a power amp with an RMS power of 1.5 to twice the RMS power handling capability of the cabs. The idea is to NEVER run the amp in to clipping. When an amp clips it is very hard on the drivers in the cab. You will see many posts on this topic on the Crown forum web site. Very informative forum if you want to know all about professional power amplifiers.
  8. thanks for the info. pretty much spot on what i was asking
  9. Munjibunga

    Munjibunga Retired Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Well then there's no need for me to jump in.
  10. well dont let me stop you, im sure there are some thread stalkers interested in what you might have to say

    :eyebrow: thats right, i see you stalkers
  11. Jim Carr

    Jim Carr Dr. Jim

    Jan 21, 2006
    Denton, TX or Kailua, HI
    fEARful Kool-Aid dispensing liberal academic card-carrying union member Musicians Local 72-147

    +1 and, more is, um, er...more! :p :p :p
  12. more speakers isnt a problem....someone help me, whats the math on a 4ohm cab and an 8ohm cab. does that come out to be something like 2.7 ohms?

    id love to be able to use my 4x10 with my 8x8, but i dont think my hartke head can stand up to that kind of abuse....
  13. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

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