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Thread: Confused about stuff

  1. #1
    MDD Supporter Nakatomi's Avatar
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    Default Confused about stuff

    Most of you are familiar with me by now. I'm a 'bit of a geek'. I know stuff about electromoronics & electrickery & am a bit of a dab hand at fixing stuff.

    BUT.. !

    I'm still having a hard time understanding amplifier & active speaker specs - or more to the point I'm puzzled by what seems to be going on in the world of speaker specs. Manufacturers lie.. er I mean bend the truth (that's called MARKETING, deary) - I've known this for ages but by how much, and why precisely? Not that it really matters a jot but I'm interested in knowing what the real power output is. You know. Just because.

    It was Yamaha who first piqued my interest when I was perusing their spec sheets. An active speaker which apparently (on paper) goes very loud (oo - and recently confirmed when I heard them in person) with "1300 watts". Ah yes but look at the figure for power consumption - as in what it pulls from the wall. ONE HUNDRED WATTS. Hmmm.

    The speaker in question was a DSR115A. I didn't happen to like the sound much, FWIW but that aside.. I found a this video in which John Young of the Disc Jockey News hoof said speaker to limiting point while measuring the power it pulled from the wall with a Kill-A-Watt meter (plugin power meter). It peaked around 100 Watts.

    Yes yes yes, I know full well that power is meaningless in these terms. It's really all about how loud it is (ie is it man enough for the job at hand) and what it sounds like. I know. But it's been bugging me that specs seem to be so far out of kilter with real world figures.

    A comment on the above video asks "so where did the other 1200Watts go, John?", to which he replies something like "it's a different kind of watts". Hmmm. Not a good answer IMHO. OH yes! Their made up watts vs real world watts you mean? Ahhh..

    At a group speaker test night a while back I'd intended to measure the power drawn from the mains so we could compare them but I couldn't find my meter in time for the event.

    Intriguing, don't you think?

  2. #2
    Senior Member DJWilson's Avatar
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    We have Lumens for the strength of a lamp @ 2m, 5m etc. It's a shame we don't have something similar for speakers.

    Surely the only real 'power level' is the Db it knocks out? But again, there's no standard test with distances, duration etc.
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    MDD Supporter Nakatomi's Avatar
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    Some enlightened manufacturers state how they arrive at their output dB figures as I think I've said. This only tends to happen on high end gear though - eg 126dB @1m, half space....

    A figure of 126dB for a speaker costing upwards of 2 grand I can believe - not 133dB for a cab costing under 800 quid! I've met 124dB once or twice in my life & it's safe to say that was from a set of speakers I could only ever dream of owning/carrying/transporting.

    There are a few outfits on youtube doing empirical measurements (with frequency response plots too!) but they sadly don't cover many models of PA.

    One day soon I might actually start measuring speaker power output. If only to satisfy my own curiosity

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    Dinosaur Excalibur's Avatar
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    And before long, some white haired old fogey is going to come along and point out that in The Good Old Days, the amps only claimed to output 100watts, but with a couple of 12" cabs we could play venues we take 5Kilowatts of line array to nowadays.

    Mind you, that was before they devalued the Watt.*


    Re your " magic " Yamahas, the only thing I can offer is that music is transient peaks, and thus you're not measuring constant unremitting current. I know that doesn't answer your question, but it's got to have something to do with it.

    * Devaluing the Watt. They didn't. It's just an old, old joke among old, old DJs.
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  5. #5
    MDD Supporter Nakatomi's Avatar
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    Quote Originally Posted by Excalibur View Post
    And before long, some white haired old fogey is going to come along and point out that in The Good Old Days, the amps only claimed to output 100watts, but with a couple of 12" cabs we could play venues we take 5Kilowatts of line array to nowadays.

    Mind you, that was before they devalued the Watt.*


    Re your " magic " Yamahas, the only thing I can offer is that music is transient peaks, and thus you're not measuring constant unremitting current. I know that doesn't answer your question, but it's got to have something to do with it.

    * Devaluing the Watt. They didn't. It's just an old, old joke among old, old DJs.

    Re the 'magic' yamaha I realise that 'music powrr' or similar is at play here but what's amusing is that the real power seems to be around 100W rms .

    Could it really be, and Watts haven't really been devalued?

    Now those plugin meters aren't known for being pinpoint accurate but... There's a 13x discrepancy to account for

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    Quote Originally Posted by DJWilson View Post
    Surely the only real 'power level' is the Db it knocks out? But again, there's no standard test with distances, duration etc.
    And no matter where I measure my 130db (or there abouts) speakers won't deliver over 90db lol
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    MDD Supporter Daryll's Avatar
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    The the age old story , people are blinded by numbers.
    I have a old Vox AC30 , that will blow most 1K systems out the door ( I dont advocate using a AC 30 for DJ work , Two...........yes...lol)

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    Dinosaur Excalibur's Avatar
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    Quote Originally Posted by Daryll View Post
    The the age old story , people are blinded by numbers.
    I have a old Vox AC30 , that will blow most 1K systems out the door ( I dont advocate using a AC 30 for DJ work , Two...........yes...lol)

    Daryll
    Tens of years ago, I did a disco where I augmented my disco sound with a Woolworths ( Yes, Woolies! ) 50w guitar combo. The reviews of the disco afterwards were that is was exceedingly good, but it was ing loud!

    They don't make Watts like they used to.
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    Senior Member ukpartydj's Avatar
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    Inflation?

    I've done the power meter speaker test and found it truly bizarre also. I've got a pair of studio monitors rated at 50W each, with no music playing they have about 60W power draw, when music is playing fairly loud, it goes to about 70W (from memory, could be slightly off). So it's about 70/100W which sounds about right.

    My PA system rated at 1500W RMS takes about 240W at normal levels! Hilarious! Probably looking at 350W full power! Very odd that my lights say 80W power draw and they draw 80W! What's going on!

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    Out of interest, what difference does watts make anyway?

    I've always taken the view that the size of the cone is going to make the biggest difference.

    My Maui 5s are about the least powered speakers I've seen (200w rms) yet they pack a punch that I feel would out perform cheaper, higher wattage speakers!

    Anyway, for me, the 'sound' of the speakers is a more important than the 'loudness' (who wants bad sounding, loud speakers?!). And sound quality can't be measured in watts or dB.

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