Is bad to under power a cab.

Discussion in 'Amps and Cabs [BG]' started by FighttheSilence, Jul 31, 2009.

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  1. The head is an Ashdown Superfly (2x250 watts @ 4 ohms). I have a Carvin 2x10 which is 400 watts @ 4 ohms and I want to add a Carvin 1x15 which is 600w @ 4 ohms when I get more money. My question is, is will having all the extra power available on the cabs be good to ensure I dont blow speakers or will it damage the hear and/or cab(s). Thanks
  2. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    Your answer lie in the FAQ. Or in a search.
  3. RustyAxe


    Jul 8, 2008
    You can't "underpower a cab" and cause damage. What does occur is that a player wants more volume, and cranks up the low powered amp to 11 ... and it clips, sending that "rough" signal to the speakers, which do their best to keep up before they croak. The wattage specs on the speakers are the MAX they can handle, either RMS (which is all that counts) or "program" (which doesn't mean diddly, but manufacturers sometimes are deceptive). Carvin, I believe, rates them RMS. In either case, it assumes a sine waveform, not a square wave.

    So ... keep your amp below clipping levels, don't be tempted to run full out because "the speakers can handle it" and you'll be fine.

    Disclaimer: someone is sure to contradict every word I said. ;)
  4. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Last time I underpowered my cabs I thank Jaweh that I read these forums in time to prevent damage! Now I never turn off my amp or put it in Standby! But it gets tricky transporting my gear to gigs that are far away, where the cabs are underpowered for sometimes a couple of hours of drive time.

    I always expect to find they aren't working when I set them up onstage.
  5. BassmanPaul

    BassmanPaul Inactive

    You'll get better results if you just add a second Carvin 2x10 and stack them vertically.

  6. Mystic Michael

    Mystic Michael Hip No Ties

    Apr 1, 2004
    New York, NY
    No contradiction here. You nailed it.

  7. Implosion


    Oct 19, 2007
    Well, when the signal is clipping it just sends a lot of power in a short perdiod of time. If the power is less than the cab/speakers can handle then there isn't a problem. Clipping in itself is not some magical "bad" thing (distortion signals anyone?).

    I wish manufacturers would remove clip-lights from amps.
  8. Sundogue


    Apr 26, 2001
    Wausau, WI
    I do believe it isn't about "rough" signal, or clipping, but about OVERPOWERING your speakers, period.

    You can overpower your speakers with an amp rated below the cab's rating because an amp has the capability to put out more than twice it's rating at times under heavy usage.

    The "idea" that underpowering your speakers and blowing them is misguided. It is about having say...a 400 watt amp running into a 600 watt cab. You aren't getting enough volume so you crank the amp, and then at some point your amp cranks out 700 or 800 watts temporarily. THAT's what blew your speakers...that underpowered amp cranked that went nuts for second.

    So, NO you can't blow your speakers from underpowering them. There's more power in that "underpowered" amp than you think.

    Somebody correct me if I'm wrong.
  9. herndonbassist

    herndonbassist Low Down Thumper

    Apr 7, 2005
    Herndon, VA - NoVa
    The easiest way to think about whether underpowering a cabinet will hurt it is to think about a volume control. Think about asking "will it hurt if I turn my amp down very low" ? I think not :D
  10. WalterBush


    Feb 27, 2005
    Yuma, Az
    Full disclosure, I'm a certified Fender technician working in a music store that carries Fender, Yamaha, and Ibanez products among others.
    Isn't there a sticky on this yet?
  11. herndonbassist

    herndonbassist Low Down Thumper

    Apr 7, 2005
    Herndon, VA - NoVa
  12. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    This topic pops up so often, I'm starting to worry about practicing at lower volume levels. When will it end? And, the previous statement was sprinkled with sarcasm, before you jump.
  13. Brent Hahn

    Brent Hahn

    Jul 25, 2009
    I'm a player, but I'm mainly an engineer. And the rookie mistake of "underpowering" I see all the time -- from experienced people who should know better -- is using an instrument cable, not a speaker cable, between the head and cab. It can make a huge difference.
  14. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I think it's time for the mods to institute word filtering, and put 'underpowering' at the top of the list. It also would be nice if there was a way to program the board so that no one can make their first post before reading the FAQs. :meh:
  15. BassmanPaul

    BassmanPaul Inactive

    Implacable Logic Bill! I think we should call you Spock - except that you like Yoda so much! :)

  16. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    Not that it doesn't get entertaining sometimes, but it is a tired old subject.
  17. seamonkey


    Aug 6, 2004
    I've found that you can take the grill off and do like a CPR move to keep the cones moving and alive.

    I've bought an old ambulance and hired off duty nurses to pump on the cones during the trip to and from the gig.

    It's worth it
  18. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Yeah! And you can get a sponge bath between sets!
  19. silky smoove

    silky smoove Supporting Member

    May 19, 2004
    Seattle, WA
    I need your help guys... My DB750 is turned off and sitting at home while I'm at my office... Do you think my Schroeder 15+L's are okay?

    I'll bet they go 10 hours without any power hitting them... That's pretty severe underpowering, I hope I don't have to go buy new cabs tomorrow :(
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