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Speaker Wattage Woes!

Discussion in 'Electrics UK' started by eveares, 13 Aug 2017.

  1. eveares

    eveares

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    So a couple of months back I got a pair of Alto True Sonic TS210 PA speakers for outdoor events. However the wattage rating of them is strange to say the least.

    According to https://www.altoproaudio.com/downloads/Alto-Professional-TS210-Spec-Sheet.pdf, they have a continuous RMS power rating of 550W and a peak power rating of 1100W.

    How can that be when Peak Power = RMS Power * √². 550W RMS should be 777W Peak.


    Further more, they have an mains input power rating of 450W (See bottom of photo).


    Even if the 550W/1100W power rating is just that of the physical drivers and not what the built in amp puts out (Block diagram in PDF says 200W HF Power Amp, 400W LF Power Amp), that does not explain the ratio between RMS and Peek rating based on that RMS is Peak Power ÷ √².

    Any ideas?

    Regards: Elliott.
     
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  3. davelx

    davelx

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    Yes, a lot of it is down to "Marketing specifications", and a lack of understanding about how audio systems work. There's not jsut RMS and Peak, there's Music Power, Peak Music Power, etc etc. Too much to reproduce here, so:

    https://en.wikipedia.org/wiki/Audio_power
     
  4. winston1

    winston1

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    I once went into Currys and asked how an amplifier they said had an output of X watts only had a mains input power of X/3 watts. They were stumped.
     
  5. EFLImpudence

    EFLImpudence

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    It's an amplifier. :whistle:
     
  6. flameport

    flameport

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    The manufacturers are liars. The output is not 1100W, 550W or anything even close to any of those.
    If the input power is really 450W, the sound output must be less than that. Probably a lot less.

    Anything claimed by audio manufacturers should generally be ignored.
     
  7. JohnW2

    JohnW2

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    Indeed, and that's even true of the instantaneous peek output and input.

    However, is there not some convention as to how the power of audio output is expressed? Given that, in normal use, they do not output a constant waveform with constant amplitude over a period of time, I would have expected that (for music, speech etc.) they would quote some sort of typical average over time (based on some 'standardised' piece of music?!!) (over real periods of time, not just over a cycle, as with RMS etc.).

    The same might also be true of the input power they quote. If that's the case, then I suppose the game they might be playing is to quote the 'average' mains input power but the peak audio output.

    Kind Regards, John
     
  8. Alec_t

    Alec_t

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    450W in and 550W out. The world's energy supply problem is solved :D.
    Yes. It's in "What??!"s.
     
  9. JohnW2

    JohnW2

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    Indeed - but, as I said, "average 450W in, peak 550W out" (or even "average 450W in, typical music average 550W out") might actually belie low efficiency, and bad news for the world'd energy supply problem!

    Kind Regards, John
     
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  11. cozycats

    cozycats

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    You are asking about loudspeaker input power, this has nothing to do with amplifiers but all to do with the physical limitations of the cone movement. Generally speakers cone excursion or x-max (max rms) is at half the power of x-damage (peak power), and is also only 3dB difference which is an almost imperceptible volume change to the human ear.

    regards
     
  12. JohnW2

    JohnW2

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    That all makes sense. However, I imagine that those who make claims about the output power of an amplifier (be they sensible, ridiculous, straightforward or misleading claims) are working on the basis that the amplifier is feeding speakers at least able to handle the amplifier's peak output - in other words, so that the amplifier, not the speakers, is the 'limiting factor'. Well, I reckon they should!

    KInd Regards, John
     
  13. ban-all-sheds

    ban-all-sheds

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    3dB will definitely be noticed by most people, and they won't describe it as "almost imperceptible" - that's generally 1dB.
     
  14. davelx

    davelx

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    That's not my experience over the last 40 years. What's your evidence?
     
  15. aptsys

    aptsys

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    Did you mean 3dB? That's a factor of 2 change.
     
  16. JohnW2

    JohnW2

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    It is, and I also thought that such was about the smallest difference that humans could perceive (particularly at high sound intensities) - but maybe I'm wrong!

    Kind Regards, John
     
  17. Spherehopper

    Spherehopper

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    I'm always amused by these specs. I'm sure I saw one once that claimed "x watts Instantaneous Peak American Music Power", probably the same item that had a frequency response of DC to Blue Light.
     
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