Speaker wpc ratings...please explain.

Discussion in 'Speakers' started by RobWil, Apr 17, 2003.

  1. RobWil

    RobWil Supporting Actor

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    If a pair of speakers are rated at 100wpc max, 500w peak what exactly does this mean? Does it mean you shouldn't run them at a full 100wpc and wouldn't this be a little extreme anyway?
    Could you still drive them with a 200wpc amp, but you'd just have to be careful or what?
     
  2. Lewis Besze

    Lewis Besze Producer

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    The 100w means continious power handling[tied to the speaker's thermal limits],with 500w peaks which normaly lasts only a few seconds.
    Yes you can hook up 200w amp,it's very unlikely,that you ever push the amp to that level,
    It depends greatly on the sensetivity of the speaker,and the listening distance,and the input of the signal[gain].
     
  3. Brett DiMichele

    Brett DiMichele Producer

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    As Lewis said (you beat me to it D'oh!)

    If a speaker is listed as 100Watts and 500Watts Peak. This
    means the voice coils can sustain a 100 watt thermal load
    without failure and momentary peaks of 500 watts. Every
    speaker ever made has a range in which it will function
    without failure from thermal overloading. If you send 1000
    watts RMS to a driver rated for 300RMS it will go up in
    smoke as the voice coils break down. (You can also do
    damage to crossover components)
     
  4. RobWil

    RobWil Supporting Actor

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    Thanks guys....I have a pair of Klipsch KG 5.2's, sensitivity 96db, at around 9 ft distance in a pretty small room. I'm thinking about driving each of them with an audiosource amp one, 200wpc bridged.
     
  5. Dave Milne

    Dave Milne Supporting Actor

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    Let's see... 96dB, 200W (that's +23dB), two of each (roughly +6dB, maybe more with room gain)...

    = 122dB. Uh, that should do it.[​IMG]
     
  6. Brett DiMichele

    Brett DiMichele Producer

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    LOL Dave

    Yeah "Uhhh Yup" I think that'll work..

    "Hold On.... I saw this in a movie once!"
     
  7. RobWil

    RobWil Supporting Actor

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    .
     
  8. Phil Iturralde

    Phil Iturralde Screenwriter

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    FYI: For a more precise & easy maximum SPL (loudness) @ your listening position (distance) vs. AMP power vs. speakers (number) vs. speaker sensitivity, ... use C. M. Collins 'excellent' SPL Calculator @ his website = How Loud Will it Go?

    Phil
     
  9. Michael R Price

    Michael R Price Screenwriter

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    Rob,

    It'll work fine. The RMS power rating is generally derived from the thermal power handling of the woofer. (I don't know where the "peak" rating comes from.) Of course, this usually does not count excursion limitations. Especially at low frequencies it might take a lot less than 100 watts to distort or damage the speaker.

    The fact that you're using a 200 watt amplifier does not mean much. Especially since your speakers are so efficient, music and movies won't demand much power. Dave was trying to say this by showing that 200 watts put into those speakers would give you 122db, which is absurd. In other words, you won't ever need to use so much power that your speakers could be damaged. (I would be surprised if your ears could stand the volume produced by 10 watts continuous with your system.) Additionally, audible distortion should warn you that you're pushing the system past its limits well before damage occurs, if that ever happens.
     
  10. Dave Milne

    Dave Milne Supporting Actor

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    Sorry Rob for the sarcasm. As Michael pointed out, I was trying to illustrate that you shouldn't have a problem... since your ears would bleed first. The only possible route to trouble would be if you have inquisitive toddlers (like I do) who might inadvertently crank the thing to max.

    In reality, more speakers are damaged by under-powered amps than overpowered, because the clipped output of an overdriven amplifier contains tons of tweeter-destroying high frequencies.

    By the way, nobody caught my math error. 96+23+6 = 125 (not 122). :b No matter.
     
  11. RobWil

    RobWil Supporting Actor

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    OK....sorry I called you an a$$hole [​IMG]
    I was just hoping it WAS sarcasm and that I hadn't missed something!
    No inquisitive toddlers...just dumbass big ones. How many times have you seen someone turn the volume up all the way becuase there was no sound? Of course it couldn't be because the wrong source was selected....that would make too much sense. It must be the VOLUME isn't turned up enough, even though you've already turned it up AS FAR AS IT GOES and there's still no sound!!! [​IMG]
    Would this hurt my speakers? [​IMG] (just kidding)
     
  12. Chu Gai

    Chu Gai Lead Actor

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    Along the line of Mr. Milne's post regarding clipping and all that, this is a little gem that was recounted some time ago by Richard Pierce whom some may recall did the crossovers for the Rocket speakers.

     
  13. RobWil

    RobWil Supporting Actor

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    So you're saying you think I'm OK then, too???? [​IMG]
     
  14. Chu Gai

    Chu Gai Lead Actor

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    yes
     
  15. DanaA

    DanaA Screenwriter

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    I also have Klipsch being driven by a pretty powerful amp. As a couple of watts can drive the speakers to 100 decibels, people might wonder why. The point is that I'm planning on keeping my power amp for a long time and power amps can last for a long time. I love my speakers, but I'm not married to them. If, for instance, I change my speakers down the line for less efficient speakers, I don't have to go through the burdon of picking up a new amp. This one will be a keeper for years to come, unless the unforseeable occurs. And, besides, I just like owning a lot of power.

    Did anyone notice that most of you guys were also on Rob's other thread too. [​IMG]
     
  16. RobWil

    RobWil Supporting Actor

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  17. Michael R Price

    Michael R Price Screenwriter

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    Dana,

    I agree with your philosophy but I'm the other way around. I want to get high-efficiency speakers eventually, and my 400 watt amp will be waiting for them! [​IMG]

    But seriously I think it's a good idea to get a better sounding amplifier (if such a thing is possible) for the same price by sacrificing a bit of power output if you don't really *need* 100+ watts. Just don't go by my example unless you're really sure you need the power. (I wasn't.)
     
  18. DanaA

    DanaA Screenwriter

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    There is a bit of Tool Time in all of this, isn't there? Men and their power amps and 300 horsepower car engines. Not something practical or at all reasonable, but there we are with out toys. [​IMG]
     

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