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  1. #1
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    Default Power to the people!

    Hello,
    Here is an interesting explanation of how amplifier power, speaker sensitivity and transient response all interact. This is part of a response Matt gave to an SRT installation concerning amplifier limiting:

    "A normal listening level might be an average of 90db but transients peaks will go at least 20 db above that. In order to preserve those transients the amp will need to produce 100 times more power than is required to maintain the 90db average. Or, in terms of voltage, 10 times the voltage swing.

    The SRT is around 90db efficiency at 1 meter from 2.83 volts RMS. That means 78db at a typical listening location 4 meters (~13 ft.) away. So, to produce 90db at the listening location the SRT needs 11.32 volts RMS from the amp. In order to preserve the transients it will need 10 times that or up to 113.2 volts RMS for very short periods of time. High perfromance amps like the Lab Gruppen are actually designed to do this and the speakers are designed to handle it."

    I hope you found this of interest, Ken

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    Dear Ken could you translate that to watts for us simple folk:)
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben

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    Hello,
    Sure, Power equals the Voltage squared divided by the impedance. Take the Voltage and square it, then divide by the impedance, 4 Ohms in this case, and you should have Watts.
    Ken

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    I have the power. :D
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

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    I love Ohm's Law.

    V=IR
    or
    I=V/R
    W=IV
    Substituting above for I
    W=VV/R=V2/R

  6. #6
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    Hello,
    Now you can begin to see why Bob Carver said that it takes 500 Watts to accurately reproduce the sound of a pair of tailor's scissors. In a well known demonstration he recorded a pair of large scissors being snapped shut. Then using a single fairly moderate speaker showed that the peak demand was greater than 500 Watts to reproduce this sound.
    Ken

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    Don't let Cathy get a hold of this. We'll never hear the end of it:D
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben

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    Those Lab Gruppen amps are impressive!!! 3200w/rms at 23lbs! (just the first model I looked at) Wow, just wow. They look like a Hybrid Class D and H combined, with all of the positive attributes, and none of the negative. Cool.
    Last edited by steveinaz; 05-16-2008 at 06:17 PM.

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  9. #9

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    Quote Originally Posted by ben62670 View Post
    Don't let Cathy get a hold of this. We'll never hear the end of it:D
    She owes all of you a big "TOLD'JA"...LOL

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  10. #10

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    Default Help my math

    So...

    P=(113.2*113.2)/4 = 3203.56?

    So in the example we'll need an amp capable of 3,203W per channel?

  11. #11

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    Quote Originally Posted by Kenneth Swauger View Post
    Hello,
    Now you can begin to see why Bob Carver said that it takes 500 Watts to accurately reproduce the sound of a pair of tailor's scissors. In a well known demonstration he recorded a pair of large scissors being snapped shut. Then using a single fairly moderate speaker showed that the peak demand was greater than 500 Watts to reproduce this sound.
    Ken
    I think he stated it was over 2000 watts. Even that doesn't seem right though

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    THANK YOU Ken!!! Please tell Matt he's GREAT!!!! LOL!

    I TOLD YOU SO!!!!!:p:D

    So just to reiterate...ALL SPEAKERS BENEFIT FROM LOTS OF POWER!!!:D:D:D:D

    I'm going to save this thread & put it in EVERY thread that asks about separate amplification.


    Quote Originally Posted by ben62670 View Post
    Don't let Cathy get a hold of this. We'll never hear the end of it:D
    Quote Originally Posted by steveinaz View Post
    She owes all of you a big "TOLD'JA"...LOL
    Last edited by cfrizz; 05-16-2008 at 09:25 PM.
    Sunfire TGP III PrePro, Sunfire Cinema Grand Signature 405wpc 5 ch. Amp, Rotel RCD-1072 CDP, Onkyo TA2600 Tape Deck, Pioneer Elite 47-A DVD, Sony 32" XBR TV, Polk RTA-8T Main Speakers, Boston VR-920 Center Channel, Boston PV-600 Subwoofer, Polk DSW 400 Subwoofer, Polk FXi-3 Surround Speakers

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    Damn, I thought I was going a little far with over 1 kW. I need MORE...

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    Quote Originally Posted by Kenneth Swauger View Post
    Hello,
    Now you can begin to see why Bob Carver said that it takes 500 Watts to accurately reproduce the sound of a pair of tailor's scissors. In a well known demonstration he recorded a pair of large scissors being snapped shut. Then using a single fairly moderate speaker showed that the peak demand was greater than 500 Watts to reproduce this sound.
    Ken
    And yet there was still clipping. ;)
    Make it Funky! :)

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    Damn!!!!

    I really like those Lab Gruppen FP 6400's

    http://www.labgruppen.com/Default.asp?Id=1706

    http://www.labgruppen.com/Default.asp?Id=1708

    1300 Watts per Channel @ 8 Ohms!!!!, I think I need two of them!, And they only cost $4300.00 each

    http://www.avsuperstore.com/moreinfo...ppen/fp%206400
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    The story goes that he visited a mad scientist friend of his, and HE was trying to re-create the sound of the scissors snipping, with 12 x 200 watt amps all gang-banged together. There wasn't enough power.

    The more I think about it, the more I feel it was 24 x 200 watt amps, for a total of 4,800 watts, and it wasn't enough. I think the 500 watts statement may be 5,000 watts. I still have that literature around here somewhere, and if I get a chance to dig it out today I will.
    Last edited by George Grand; 05-17-2008 at 07:47 AM.

  17. #17

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    Quote Originally Posted by Kenneth Swauger View Post
    Hello,
    Now you can begin to see why Bob Carver said that it takes 500 Watts to accurately reproduce the sound of a pair of tailor's scissors. In a well known demonstration he recorded a pair of large scissors being snapped shut. Then using a single fairly moderate speaker showed that the peak demand was greater than 500 Watts to reproduce this sound.
    Ken
    I was waiting on somebody to bring this up.

    Thanks,
    Roy

  18. #18

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    From the Carver 1984 Sales Brochure.....

    "Once Bob Carver visited a famous sound researcher who was attempting to recreate the sound of a "snip" of an ordinary pair of scissors. He used no less than 24-200 watt amplifiers for playback., yet when viewed on an oscilloscope it was apparent that the top of that instantaneous transient was being distorted. Believe it or not, he needed more power. "
    In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence.

    The best way to enjoy digital music reproduction is to never listen to good analogue reproduction.

  19. #19

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    Quote Originally Posted by treitz3 View Post
    From the Carver 1984 Sales Brochure.....

    "Once Bob Carver visited a famous sound researcher who was attempting to recreate the sound of a "snip" of an ordinary pair of scissors. He used no less than 24-200 watt amplifiers for playback., yet when viewed on an oscilloscope it was apparent that the top of that instantaneous transient was being distorted. Believe it or not, he needed more power. "
    Maybe his speakers or the mic that recorded the sound were to blame as well.
    Polk Audio SDA SRS 1.2TL's
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  20. #20

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    Because of this theory I used to have over 13KW for my HT system. A friend still has about 10KW. Power like that gives you a a good snapshot of a live band fully amplified. I'm a 200W tube guy now, thank heavens...
    madmax
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D

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    Someone ought to post this over on Audioholics :p:D

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  22. #22

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    :D WAAAAAAAAAAAAAAAAAAA!!!!

    Thanks Ron, I just blew water all over my monitor!

    Go ahead & do it. I'll be along shortly to scrape up what's left of your torn apart carcass!!!:D:D:D:D WAAAAAAAAAAAAAAAAAAA!!!!

    (In my best audiophile Audioholics voice) NOBODY NEEDS ANYTHING MORE THAN A RECEIVER! AND IF YOU'RE DELUSIONAL ENOUGH TO THINK YOU NEED MORE POWER THEN BUY A CHEAP PRO AMP!!!

    Quote Originally Posted by Ron Temple View Post
    Someone ought to post this over on Audioholics :p:D
    Last edited by cfrizz; 05-17-2008 at 09:13 PM.
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  23. #23

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    Now thats funny.:D

    engtaz

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    Quote Originally Posted by cfrizz View Post
    :D WAAAAAAAAAAAAAAAAAAA!!!!

    Thanks Ron, I just blew water all over my monitor!

    Go ahead & do it. I'll be along shortly to scrape up what's left of your torn apart carcass!!!:D:D:D:D WAAAAAAAAAAAAAAAAAAA!!!!

    (In my best audiophile Audioholics voice) NOBODY NEEDS ANYTHING MORE THAN A RECEIVER! AND IF YOU'RE DELUSIONAL ENOUGH TO THINK YOU NEED MORE POWER THEN BUY A CHEAP PRO AMP!!!
    Maybe tomorrow. I've posted a few times over there regarding amps that I'm familiar with and it usually kills the thread dead or is totally ignored :D. Yep, maybe stirring the pot is totally in order.

    Combo rig:

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  25. #25

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    Quote Originally Posted by Ron Temple View Post
    Maybe tomorrow. I've posted a few times over there regarding amps that I'm familiar with and it usually kills the thread dead or is totally ignored :D. Yep, maybe stirring the pot is totally in order.
    Ignorance is bliss.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

  26. #26
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    Quote Originally Posted by Lasareath View Post
    Maybe his speakers or the mic that recorded the sound were to blame as well.
    Nope, always more power.:D

    And this coming from a guy who used 15wpc tubes... :o

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    if its all the same I will just keep my measley 20watt Manley. Again, watts are easily manipulated just like some members.

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  28. #28

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    [QUOTE Again, watts are easily manipulated just like some members.[/QUOTE]

    Thankfully that isn't true about the definition of a Watt.

    However, there are people, for what ever reason, may try to change the meaning/definition of a Watt.

    When you pay the electric bill a Watt is a Watt.

    When you turn on a 60, 100 or 150 watt light bulb a Watt is a Watt.

    A tube Watt is the same as a SS Watt with the same level of distortion and frequency response.

    A foot is a foot weather you use a wooden ruler or a metal ruler.

    A watt is equal to voltage times current. It just plain logic.

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    Quote Originally Posted by bikezappa View Post
    [QUOTE Again, watts are easily manipulated just like some members.
    Thankfully that isn't true about the definition of a Watt.

    However, there are people, for what ever reason, may try to change the meaning/definition of a Watt.

    When you pay the electric bill a Watt is a Watt.

    When you turn on a 60, 100 or 150 watt light bulb a Watt is a Watt.

    A tube Watt is the same as a SS Watt with the same level of distortion and frequency response.

    A foot is a foot weather you use a wooden ruler or a metal ruler.

    A watt is equal to voltage times current. It just plain logic.[/QUOTE]

    and bull**** is bull**** no matter how much paint and pretty you put on it!!!! its bull**** to believe you need some magic number of watts to enjoy HT or music, eff sissors, how about a guillotine?????????

    i pretty much agree with you but the tube/ss statement is not fact, their are voltage swings with tubes that throw the figures out of whack.

    RT1--you keep biting and I'll keep reelin
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    Subs-Twin Polk CSW200
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    Everthing Matters...Tubes Rule...and It's Over until it's Not Over

  30. #30

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    [QUOTE=reeltrouble1;860252]i pretty much agree with you but the tube/ss statement is not fact, their are voltage swings with tubes that throw the figures out of whack.QUOTE]

    The voltages can vary and change in any manner possible but the definition of a watt still remains the same. That's what makes the formular so beautiful. The formular is more complicated for changes is frequency applied to a capacitive and inductive circuit however.

    And yes people for what ever reason can confuse the peak power and the RMS power to a speaker and to a light bulb. The peak power, watts, can change with time. I think the origin of this thread is to show that there can be very high peak power delivery to speakers.

    However, one watt of power at 60 cycles applied to a speaker will sound the same weather it comes from a SS or tube amplifier or even from a transformer connected to 120 Volt outlet. You just must be very accurate measuring the volts and amps. And that can be tricky if there are fast voltage changes. You would need a scope then not just a volt and amp meter.

    Can you hear the difference between scissors recorded and played back with a 200,000 watt amp and a 20 watt amp? I don't know I never tried it. It would probably depend on the sound level of the playback of the scissors. Do you want to hear scissors playbacked at 120db? Then you may need a 200,000 watt amp. Grin

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