Power to the people!

[Deleted User] · May 2008

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

ben62670 · May 2008

Dear Ken could you translate that to watts for us simple folk:)

[Deleted User] · May 2008

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

Face · May 2008

I have the power.

bikezappa · May 2008

I love Ohm's Law.

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

[Deleted User] · May 2008

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

ben62670 · May 2008

Don't let Cathy get a hold of this. We'll never hear the end of it:D

steveinaz · May 2008

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.

steveinaz · May 2008

ben62670 wrote: »

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

fatchowmein · May 2008

So...

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

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

Music Joe · May 2008

Kenneth Swauger wrote: »

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

cfrizz · May 2008

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.

ben62670 wrote: »

Don't let Cathy get a hold of this. We'll never hear the end of it:D

steveinaz wrote: »

She owes all of you a big "TOLD'JA"...LOL

amulford · May 2008

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

gidrah · May 2008

Kenneth Swauger wrote: »

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.

George Grand · May 2008

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.

engtaz · May 2008

Kenneth Swauger wrote: »

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

treitz3 · May 2008

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. "

madmax · May 2008

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

Ron Temple · May 2008

Someone ought to post this over on Audioholics

:D

cfrizz · May 2008

:eek::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!!!:eek::eek::eek::eek::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!!!:mad:

Ron Temple wrote: »

Someone ought to post this over on Audioholics :D

engtaz · May 2008

Now thats funny.:D

engtaz

Ron Temple · May 2008

cfrizz wrote: »

:eek::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!!!:eek::eek::eek::eek::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!!!:mad:

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

. Yep, maybe stirring the pot is totally in order.

Face · May 2008

Ron Temple wrote: »

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 . Yep, maybe stirring the pot is totally in order.

Ignorance is bliss.

zingo · May 2008

Lasareath wrote: »

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...

reeltrouble1 · May 2008

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

RT1--Thats my line
Now bite my hook

bikezappa · May 2008

[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.

reeltrouble1 · May 2008

bikezappa wrote: »

[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 **** is **** no matter how much paint and pretty you put on it!!!! its **** 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

bikezappa · May 2008

reeltrouble1 wrote: »

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

reeltrouble1 · May 2008

bike, i think we are saying the exact same thing.

RT1

[Deleted User] · May 2008

"gentlemen, there's no fighting in the war room!"
This is only one area of accurate sound reproduction and was only intended to show how demanding reproducing wide dynamic program material can be. Amplifying power is only one part of a total goal; speaker efficiency and listening distance are part of it, as well. This is a multi-faceted hobby and all parts of it are important and interrelated.
Maybe for one person having a high efficiency speaker and relatively low power output is the answer. For another a different combination works best, medium efficiency speakers and a moderately powerful amplifier. It's the final level of individual satisfaction that matters.
I have a friend who is perfectly happy sitting on his sub-woofer cabinet (he maintains he gets the bass through his spinal column) and a pair of Stax electrostatic headphones fed directly by an SACD player. Audio bliss!
Have fun, Ken

steveinaz · May 2008

Well, this post adresses the proper "scale" of music. People always talk about frequency response, distortion, signal to noise, etc, etc. Rarely do you hear anyone speak of the power needed to accurately reproduce music's scale/dynamic sweep.

Awhile back, I responded to a thread that "I have never heard drums accurately reproduce on any audio system, at any price"...this topic probably explains why.

Cool stuff Ken.

Power to the people!

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