Originally Posted by weltersys
Amplifiers amplify voltage with a linear output compared to the input until the amp clips, or current limits.
Loudspeakers have differing impedance with differing frequency, but will respond linearly to the delivered amp voltage, as long as the voice coil has not heated to the point where the impedance rises, (thermal compression), and the speaker has not exceeded Xmax.
With dynamic music as Pano listens to (16 dB or more crest factor) thermal compression is not an issue.
I just put a Nora Jones CD in my Alesis Masterlink ( a CD mastering unit), the VU meters seldom went below -9 dbfs...
With the volume wars raging, many CDs now have similar dynamic range to pink noise, which is only 12 dB.
Obviously, any amp pushed beyond it's linear operating range will no longer be linear.
A speaker's phase may vary well over 720 degrees over a given frequency range, I am unaware of phase having any affect on the output of any amplifiers I have used.
Perhaps you can give a reference to the amps you are referring to that can't maintain their voltage output into "phase angles of -60 deg for eg".
Art
Amplifiers amplify voltage with a linear output compared to the input until the amp clips, or current limits.
Loudspeakers have differing impedance with differing frequency, but will respond linearly to the delivered amp voltage, as long as the voice coil has not heated to the point where the impedance rises, (thermal compression), and the speaker has not exceeded Xmax.
With dynamic music as Pano listens to (16 dB or more crest factor) thermal compression is not an issue.
I just put a Nora Jones CD in my Alesis Masterlink ( a CD mastering unit), the VU meters seldom went below -9 dbfs...
With the volume wars raging, many CDs now have similar dynamic range to pink noise, which is only 12 dB.
Yes, I am aware some amplifiers current limit voltage output at low impedance, exactly why I wrote "amplifiers amplify voltage with a linear output compared to the input until the amp clips, or current limits".
Obviously, any amp pushed beyond it's linear operating range will no longer be linear.
A speaker's phase may vary well over 720 degrees over a given frequency range, I am unaware of phase having any affect on the output of any amplifiers I have used.
Perhaps you can give a reference to the amps you are referring to that can't maintain their voltage output into "phase angles of -60 deg for eg".
Art
Hello Art,
Since loudspeakers refuse to act like well behaved resistors, with impedance changes going from resistive to inductive and capacitive, depending on the frequency. Obvious to me is amplifiers which current limit from 8 ohms to 4 ohms , they will tend to have more issues driving such impedances with changing phase angles..
Look up Speaker Phase Angle Vs. Transistor Dissipation.
Since loudspeakers refuse to act like well behaved resistors, with impedance changes going from resistive to inductive and capacitive, depending on the frequency. Obvious to me is amplifiers which current limit from 8 ohms to 4 ohms , they will tend to have more issues driving such impedances with changing phase angles..
Look up Speaker Phase Angle Vs. Transistor Dissipation.
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OK, just for fun I ran thru 12 fairly dynamic tracks. They have an average to peak of about 19dB. I ran them all louder than normal, volume knob at 12:00. Some of the tracks I couldn't take that loud. Jazz, Classical, Bluegrass, Vocal, Pop, Rock.
The highest peaks I saw on the o'scope where 6 volts. That's it. Six volts, peak. My EL34 amp clips at about 22 volts. Never got anywhere near that. I turned the scope trace up to see any tiny peaks, ran it fast and slow. 6V was it. Mostly 4V peak when playing loud.
6V peak into 8 ohms is 4.5W peak. An amp that can do a clean 3W RMS would not clip.
Surprising, but true.
Less efficient speakers and/or a bigger space would change that.
The highest peaks I saw on the o'scope where 6 volts. That's it. Six volts, peak. My EL34 amp clips at about 22 volts. Never got anywhere near that. I turned the scope trace up to see any tiny peaks, ran it fast and slow. 6V was it. Mostly 4V peak when playing loud.
6V peak into 8 ohms is 4.5W peak. An amp that can do a clean 3W RMS would not clip.
Surprising, but true.
Less efficient speakers and/or a bigger space would change that.
Pano,
those that are arguing seem to be of the ilk that refuse to accept that science and arithmetic can be used to explain/prove everything.
They don't want to believe that the average level we listen to can be measured.
They don't want to believe that the peak to average can be measured.
They don't want to believe that most systems will sound better, if there is a significant overhead to cope with transients that should be at least 40 times the average power level and that some music styles/playing/singing requires more than 100 times the average level as an overhead for peak transients.
those that are arguing seem to be of the ilk that refuse to accept that science and arithmetic can be used to explain/prove everything.
They don't want to believe that the average level we listen to can be measured.
They don't want to believe that the peak to average can be measured.
They don't want to believe that most systems will sound better, if there is a significant overhead to cope with transients that should be at least 40 times the average power level and that some music styles/playing/singing requires more than 100 times the average level as an overhead for peak transients.
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oon_the_kid
Don't know if you have come across this thread,
http://www.diyaudio.com/forums/soli...er-do-you-really-need-domestic-listening.html
Don't know if you have come across this thread,
http://www.diyaudio.com/forums/soli...er-do-you-really-need-domestic-listening.html
Thanks Mooly - I remember your thread. I'll read thru it again. Looks like you are saying exactly the same thing I am.
Andrew, I understand a.wayne's argument - sometimes you do need a lot of power. It all depends on what you are trying to do. For most of us with reasonably efficient speakers in small to medium rooms, a few watts is all you really need. You are correct, it can be calculated and measured. Has anyone reading this actually bothered to do it?
I see the test tones have been downloaded 14 times.
Andrew, I understand a.wayne's argument - sometimes you do need a lot of power. It all depends on what you are trying to do. For most of us with reasonably efficient speakers in small to medium rooms, a few watts is all you really need. You are correct, it can be calculated and measured. Has anyone reading this actually bothered to do it?
I see the test tones have been downloaded 14 times.
The majority of that camp don't believe ANYTHING can be measured or even worse - all gods forbid - CALCULATED!
And don't EVER mention that you have anything even in faint resemblance of education in electronics related matters....
Thanks Pano and i'm not sure what camp Andrew is thinking of , must be camp david ..?
Pano , what DB level , Nominal? listening distance ? speakers must be 100db/1w/m..?
Firstly the calculation is academic, the intent of my request was not to dispute the obvious, funny how safety pin T waited for the test results to comment , that speak volumes about those from camps that hate to do the practical.
Pano is on his way to proving my point , he is using an amp more than 4 times the power requirement vs what he needs, plug in a 6 watter and i'm sure the audible degradation would be obvious.
Keep follow T .....
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No Wayne, I'm not on my way to proving your point. You can't twist the results to fit your needs. I did the test you asked for, and got the results I posted. This clearly proves my point, not yours.
I do have several 6 watt amps, both tube and solid state. They don't clip when running this loud, but won't go much louder. Some of them sound even better than the 30W amp. I just used the 30W because it was sitting there.
To answer your questions:
Listening distance = 3 meters
SPL average = 85dB C weighted.
Speakers are overall about 95dB/W/1M, best guess. Maybe less.
Room is about 104 cubic meters. (3700 ft^3)
I do have several 6 watt amps, both tube and solid state. They don't clip when running this loud, but won't go much louder. Some of them sound even better than the 30W amp. I just used the 30W because it was sitting there.
To answer your questions:
Listening distance = 3 meters
SPL average = 85dB C weighted.
Speakers are overall about 95dB/W/1M, best guess. Maybe less.
Room is about 104 cubic meters. (3700 ft^3)
An average level of -20 would imply a dynamic range of 40 dB, something I don't see on any of the VU meters I use with most music.
I understand that a DVM will not properly measure average level on music or noise (integration time is too slow), my question was in reference to how you determined various music sources average -16 to -22 dBfs.
That is, what software are you using to measure the RMS value of the music?
As a reference, I'm curious what your software reads as the average level of pink noise and a sine wave run to 0dBfs.
Art
I use Goldwave to determine the RMS value of the track. There are other softwares that will do that, too. On a full scale sine, it shows an RMS value of -3dB. On pink noise it depends on the noise. Generally if the pink noise has its peaks at 0dB, then the RMS value shows -15dB. Full scale white nose is -4.77dB by its calculation.
Hope that helps.
Hope that helps.
Thanks, exactly what I was looking for .
Interesting that pink noise only averages 1 dB louder than what you mentioned the average for pop recordings.
Headroom is great, for sure. It's best not to underestimate how much you need.
But in my case 4 to 5 times the average power isn't even 1W.
I do need more than that for dynamics, tho. Maybe 8 to 10 times average listening power.How is this for a cheat?
Just go by IMAX standards at the seated position--121dB for sub bass and 110dB (??) for the mid/highs? That would take care of movies and classical quite well--the huge dynamics of both would be easily covered.
I'm not there--but 104dB peaks for mids/highs and 112dB sub bass at the couch works for everything I listen to. Unless I sneak in the 1812 Overture, pipe organs or Black Hawk Down... there is always a limit I guess.
Just go by IMAX standards at the seated position--121dB for sub bass and 110dB (??) for the mid/highs? That would take care of movies and classical quite well--the huge dynamics of both would be easily covered.
I'm not there--but 104dB peaks for mids/highs and 112dB sub bass at the couch works for everything I listen to. Unless I sneak in the 1812 Overture, pipe organs or Black Hawk Down... there is always a limit I guess.
Please see post number 13.
https://production.diyaudio.com/community/index.php?posts/2799427/
https://production.diyaudio.com/community/index.php?posts/2799427/
I read that, but how do I use the multimeter (never used one before) and do I need anything else? And where do I put the probes? Any dangers?
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