yes, to be more precise.....
the 1974 FTC ruling is what we go by, ac voltage developed across a dummy load resistor load tells you the power, the sine wave average power, that is at the onset of clipping or a specified THD...
power ratings in any amp is a useful metric to dimension the parts that goes into the making of an amp, any amp.....when music is playing in such an amp, then that is a different ball of wax altogether...
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I remember reading in an old (very old, about 45-50 years) an article in HiFiNews on how to pass a 3W amplifier into a 100W one, without changing something in it.
Changing the mains voltage (for instance, from 230 to 250V).
Changing the load (from the usual 8ohms to 2 ohms).
Changing the signal, from a pure sinewave to a short pulse.
Changing the bandwith of the measure.
Changing the duration of the measure (instead of something like an hour, just 10 seconds)
Changing the meaning of "power" calculation (from "RMS" to musical to PMPO ...)
Just the miracle of words and "alternative facts" !
Changing the mains voltage (for instance, from 230 to 250V).
Changing the load (from the usual 8ohms to 2 ohms).
Changing the signal, from a pure sinewave to a short pulse.
Changing the bandwith of the measure.
Changing the duration of the measure (instead of something like an hour, just 10 seconds)
Changing the meaning of "power" calculation (from "RMS" to musical to PMPO ...)
Just the miracle of words and "alternative facts" !
and all that is due to the fact that music has much lower energy content than the sine waves use as basis for calculations of amplifier designs, so that even a 1000 watt amplifier will be putting out 5 watts real power into a real speaker playing music...
At home , maybe.
For PRO use such as PA, DJ or Musical Instrument, you will not only put out full power,for long hours, but often overdrive it into distortion.
For PRO use such as PA, DJ or Musical Instrument, you will not only put out full power,for long hours, but often overdrive it into distortion.
In the instrument world you get to full power for sure, but in the pro /DJ world you really only approach about 1/4 power on average, maybe about half for the subs when playing tracks like Dark Horse (plug-the-sub-in-the-wall bass). That is with A LOT of distortion. And DJs do live with the distortion, it is PART of what sets the roof on fire and therefore necessary. True professional audio rigs aren’t even run *that* hard continuously - the big companies can’t risk a reputation for poor sound and the blown drivers they would get on every gig. The sound is relatively clean at about 10% of power on average if you are using compressors and limiters properly, which kind of corresponds to the newer “1/8 power” standard they are using now for FTC preconditioning and current draw ratings. It used to be 1/3 power back in the 70’s, and very few amps would make the cut. Very few would make it today. And regardless, the distortion is pretty bad at those kind of levels.
For speakers, this is the power
a) at which they can work for a long time without damage;
b) withstand a minute;
c) withstand the impulse.
Distortion (THD) is measured at 82 dB 🙁
a) at which they can work for a long time without damage;
b) withstand a minute;
c) withstand the impulse.
Distortion (THD) is measured at 82 dB 🙁
Theater and PA speakers are far more efficient. Usually very high efficiency horns. So they may need 5 times less power for the same sound level.
Bagpipes, or properly warpipes. Designed to be played through the fog to terrorize the enemy. Not in a room. And yea, there is more than one tune written for them even though it seems that is all marching bands can learn. I am not sure what dB they can reach, but as they can cause pain, it is above 110dB.
Bagpipes, or properly warpipes. Designed to be played through the fog to terrorize the enemy. Not in a room. And yea, there is more than one tune written for them even though it seems that is all marching bands can learn. I am not sure what dB they can reach, but as they can cause pain, it is above 110dB.
In D'Agostino's latest offering the analog meter sensitivity was changed so that customers would have have something to look at. In testing at full power the needles almost bent. Too much to ask for a range switch on a $125,000 amp.
still doubtful that what the meter displayed was the real power playing music.....
after all how do you measure power in terms of music? has anyone come up with a metric or procedures?
that meter can slam the stops and get bent but still that is no measure of real power...
i use a power meter feeding the amp to display power while music is playing, power varies when at idle, at low volumes and at very high levels....you will find that it is not constant with use....
this is what i actually use to monitor power real time....https://shopee.ph/20-100A-AC-LCD-Di...TYNijSU_2y7H7QwJr3urY338PLxzqbcmQFCfoFBtF9OE8
after all how do you measure power in terms of music? has anyone come up with a metric or procedures?
that meter can slam the stops and get bent but still that is no measure of real power...
i use a power meter feeding the amp to display power while music is playing, power varies when at idle, at low volumes and at very high levels....you will find that it is not constant with use....
this is what i actually use to monitor power real time....https://shopee.ph/20-100A-AC-LCD-Di...TYNijSU_2y7H7QwJr3urY338PLxzqbcmQFCfoFBtF9OE8
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Meters are useful for setup and periodic calibration, especially for high power rigs. That is if they mean something. Cosmetic meters say more about customers than the amps.
Digital sources have a max level (lets call it 0dB) and they deliver a certain voltage say 1V.
The amp can output 25W into 4 ohm = 10V
With 20dB of gain we cover the whole dynamic
The speaker has 86dB/1W, so a peak SPL of 100dB can be reached
I analyzed a track irecently played and recorded
Mixdown Pharao by BanSuri | Ban Suri | Free Listening on SoundCloud
So the total longterm power is only 25% or 6.25W and SPL 94dB.
No meter needed, an overload LED would be enough.
I also analyzed another extreme techno track and it had 13W and 97dB.
The amp can output 25W into 4 ohm = 10V
With 20dB of gain we cover the whole dynamic
The speaker has 86dB/1W, so a peak SPL of 100dB can be reached
I analyzed a track irecently played and recorded
Mixdown Pharao by BanSuri | Ban Suri | Free Listening on SoundCloud
So the total longterm power is only 25% or 6.25W and SPL 94dB.
No meter needed, an overload LED would be enough.
I also analyzed another extreme techno track and it had 13W and 97dB.
My Technics receiver uses dual 0 to 100W "power level" flourescent bargraphs that I would assume are supposedly calibrated for 8 ohm speakers.
Since I'm using 4 ohm systems, I don't pay much attention to the dancing graphs, all I know is that at 2 to 5 watts peaks on those meters, the music is at a comfortable level.
one thing is sure, the amplitude peaks of any music can only approach the rails and never beyond it...
again the energy content of music is never going to approach that of the sine wave, although they sine and the music can clip to the rails, this is the physics of it.
and about the speakers, an 8 ohm so called is never really 8 ohms from 20hz to 20khz, it varies all over the place...
so whatever calibration was done with the amp using sine waves, it does not mean uch with music...
again the energy content of music is never going to approach that of the sine wave, although they sine and the music can clip to the rails, this is the physics of it.
and about the speakers, an 8 ohm so called is never really 8 ohms from 20hz to 20khz, it varies all over the place...
so whatever calibration was done with the amp using sine waves, it does not mean uch with music...
The oscilloscope usually shows the low frequency envelope (bass, drum). Small peaks (high and mid frequencies) are visible on it. Like saw teeth. When constrained, they disappear first. Are replaced by the products of distortion of the main (powerful) tone.
so how do you reduce that to a figure like watts? has anyone tried and done it?...
for me the simple power monitor at the ac power source to the amp gives a better picture...for class A maybe the readings will be more or less constant, but with AB it will be different...
for me the simple power monitor at the ac power source to the amp gives a better picture...for class A maybe the readings will be more or less constant, but with AB it will be different...