[apa]

Can anyone explain the difference between these two readings in Adobe
Audition's Amplitude Statistics window?
Thanks, Andy

[Randy Yates]

apa writes:

Can anyone explain the difference between these two readings in Adobe
Audition's Amplitude Statistics window?
Thanks, Andy

If you gun your engine at 10:00:00am for 5 seconds to go from 0 to 60
MPH, you might use 350 horsepower during those 5 seconds. However, if
you then level off at 60 and drive that speed for an hour, your average
over the entire hour may only be something like 60 horsepower.

Power is energy per time. Depending on the extent of the time, you can
consider it "total power" or "average power" over some averaging time.
--
% Randy Yates % "The dreamer, the unwoken fool -
%% Fuquay-Varina, NC % in dreams, no pain will kiss the brow..."
%%% 919-577-9882 %
%%%% % 'Eldorado Overture', *Eldorado*, ELO
http://www.digitalsignallabs.com

[apa]

On Jan 9, 3:53 pm, Randy Yates wrote:
apa writes:
Can anyone explain the difference between these two readings in Adobe
Audition's Amplitude Statistics window?
Thanks, Andy

If you gun your engine at 10:00:00am for 5 seconds to go from 0 to 60
MPH, you might use 350 horsepower during those 5 seconds. However, if
you then level off at 60 and drive that speed for an hour, your average
over the entire hour may only be something like 60 horsepower.

Power is energy per time. Depending on the extent of the time, you can
consider it "total power" or "average power" over some averaging time.
--
% Randy Yates % "The dreamer, the unwoken fool -
%% Fuquay-Varina, NC % in dreams, no pain will kiss the brow..."
%%% 919-577-9882 %
%%%% % 'Eldorado Overture', *Eldorado*, ELOhttp://www.digitalsignallabs.com

Here's the confusion more specifically. Adobe Audition Statistics
window has two different averaged values for the same selected audio
segment (i.e. the same time period). One they call "Average Power RMS"
which would seem straight forward except that they also have a "Total
Power RMS". This value tends to be slightly lower than the "Average
Power RMS" value. I'm wonder what the difference in the averaging is.

[Richard Crowley]

"apa" wrote ...
Here's the confusion more specifically. Adobe Audition Statistics
window has two different averaged values for the same selected audio
segment (i.e. the same time period). One they call "Average Power RMS"
which would seem straight forward except that they also have a "Total
Power RMS". This value tends to be slightly lower than the "Average
Power RMS" value. I'm wonder what the difference in the averaging is.

I would guess that the "Total" number is the RMS average over the entire
timeline. The question is what period the "Average" number is integrated
over?

[[email protected]]

X-no-archive:
On Jan 9, 5:29*pm, "Richard Crowley" wrote:
"apa" wrote ...

Here's the confusion more specifically. Adobe Audition Statistics
window has two different averaged values for the same selected audio
segment (i.e. the same time period). One they call "Average Power RMS"
which would seem straight forward except that they also have a "Total
Power RMS". This value tends to be slightly lower than the "Average
Power RMS" value. *I'm wonder what the difference in the averaging is..

I would guess that the "Total" number is the RMS average over the entire
timeline. The question is what period the "Average" number is integrated
over?

well first off the term "RMS power" is not really valid...

Irms * Vrms = Power average..

But lots of people use the term "RMS power" incorrectly when they
really mean average power.

And the total average power integrated over a time would be units of
energy... maybe thats what they mean..

i.e. if you burned a 60 Watt (power) lightbulb for 1 hour that would
be 60 Watthours of energy.

What are the units that they use for both terms?

And do some experiments, create a tone at -10 dBFS for 1 minute and
see what it reads. Then make it 1 minute one and 1 minute off in a 2
minute "song" and see what it reads.. That is probably the only way
you are going to be able to know for sure what it IS doing..



Mark

[Norbert Hahn[_2_]]

wrote:

X-no-archive:
On Jan 9, 5:29*pm, "Richard Crowley" wrote:
"apa" wrote ...

Here's the confusion more specifically. Adobe Audition Statistics
window has two different averaged values for the same selected audio
segment (i.e. the same time period). One they call "Average Power RMS"
which would seem straight forward except that they also have a "Total
Power RMS". This value tends to be slightly lower than the "Average
Power RMS" value. *I'm wonder what the difference in the averaging is.

I would guess that the "Total" number is the RMS average over the entire
timeline. The question is what period the "Average" number is integrated
over?

well first off the term "RMS power" is not really valid...

Irms * Vrms = Power average..

That's right in the real world. In software dealing with samples most
likely coming from a mic that converts air pressure changes into
voltage...

You may change the windows size that Auditions uses for calculation
the average values. It defaults to 10 ms - at least in my version 1.5.
One of the advantages of Audition is its online help - every parameter
which can be configured is explaned along with its side effects. You
may press F1 any time and the html browser comes up and shows help.

And do some experiments, create a tone at -10 dBFS for 1 minute and
see what it reads. Then make it 1 minute one and 1 minute off in a 2
minute "song" and see what it reads.. That is probably the only way
you are going to be able to know for sure what it IS doing..

That's always a good idea.

Norbert

[Randy Yates]

writes:
[...]
And the total average power integrated over a time would be units of
energy...

Hi Mark,

That doesn't make sense. You don't integrate total average power - it's
already integrated, i.e., it's just a constant.

Perhaps what you meant was "the instantaneous power integrated over a
time would be units of energy," to which I would agree.
--
% Randy Yates % "Ticket to the moon, flight leaves here today
%% Fuquay-Varina, NC % from Satellite 2"
%%% 919-577-9882 % 'Ticket To The Moon'
%%%% % *Time*, Electric Light Orchestra
http://www.digitalsignallabs.com

[Norbert Hahn[_2_]]

"Richard Crowley" wrote:

"apa" wrote ...
Here's the confusion more specifically. Adobe Audition Statistics
window has two different averaged values for the same selected audio
segment (i.e. the same time period). One they call "Average Power RMS"
which would seem straight forward except that they also have a "Total
Power RMS". This value tends to be slightly lower than the "Average
Power RMS" value. I'm wonder what the difference in the averaging is.

I would guess that the "Total" number is the RMS average over the entire
timeline. The question is what period the "Average" number is integrated
over?

Both values are always calculated over the highlighted part of the song.
In nothing is highlighted the total song is evaluated.
When you click "help" on the statistics windows and then goto "Waveform
Statistics options" you can read:
"Average RMS Power - Shows the average amplitude. This value reflects
perceived loudness."
"Total RMS Power - Represents the total power of the entire selection."

HTH
Norbert

[Randy Yates]

Norbert Hahn writes:

"Richard Crowley" wrote:

"apa" wrote ...
Here's the confusion more specifically. Adobe Audition Statistics
window has two different averaged values for the same selected audio
segment (i.e. the same time period). One they call "Average Power RMS"
which would seem straight forward except that they also have a "Total
Power RMS". This value tends to be slightly lower than the "Average
Power RMS" value. I'm wonder what the difference in the averaging is.

I would guess that the "Total" number is the RMS average over the entire
timeline. The question is what period the "Average" number is integrated
over?

Both values are always calculated over the highlighted part of the song.
In nothing is highlighted the total song is evaluated.
When you click "help" on the statistics windows and then goto "Waveform
Statistics options" you can read:
"Average RMS Power - Shows the average amplitude. This value reflects
perceived loudness."
"Total RMS Power - Represents the total power of the entire
selection."

Norbert,

What do you mean by "average amplitude?"

Power is joules / second. volts are joules / coulomb. amps are coulombs
/ second. v * i = joules / second, or power. If you integrate v * i over
time, you get the total joules over that time. If you then divide the
total joules by the time period T, you get power back again.

--Randy

PS: I'm assuming that you mean "Average Power" and "Total Power," i.e.,
that the "RMS" is a misnomer. Volts can be RMS, not power.
--
% Randy Yates % "Maybe one day I'll feel her cold embrace,
%% Fuquay-Varina, NC % and kiss her interface,
%%% 919-577-9882 % til then, I'll leave her alone."
%%%% % 'Yours Truly, 2095', *Time*, ELO
http://www.digitalsignallabs.com

[Peter Larsen[_3_]]

Richard Crowley wrote:

"apa" wrote ...

Here's the confusion more specifically. Adobe Audition Statistics
window has two different averaged values for the same selected audio
segment (i.e. the same time period). One they call "Average Power
RMS" which would seem straight forward except that they also have a
"Total Power RMS". This value tends to be slightly lower than the
"Average Power RMS" value. I'm wonder what the difference in the
averaging is.

I would guess that the "Total" number is the RMS average over the
entire timeline. The question is what period the "Average" number is
integrated over?

Assuming some slight amount of logic in the wordings Total RMS is that, ie.
the entire piece. Averaging is done with a time window with adjustable
width. Default is 50 ms, I always use 300 ms. My vague perception is that
the "average" is then the average of the sliding average.

My choice when aligning files numerically is to always use the average, and
it is very rare that it needs adjusting because it "sounds wrong". What
could void it would be a file with either repetive close transients or a
lack of bass. It is a bit more work than using the automated process, but it
seems to be less work overall because less after-adjustments or re-doings
are likely to be needed.

Kind regards

Peter Larsen

[William Sommerwerck]

I've waited to chime in on this...

An RMS measurement manipulates data in a particular way. (It's the square
root of the average of the sum of the squares.) It stands alone. The idea of
a "total" or "average" RMS measurement strikes me as odd, and likely
meaningless.

The only valid explanation is going to come from the software's publisher.

[Don Pearce[_2_]]

On Fri, 09 Jan 2009 15:53:16 -0500, Randy Yates
wrote:

apa writes:

Can anyone explain the difference between these two readings in Adobe
Audition's Amplitude Statistics window?
Thanks, Andy

If you gun your engine at 10:00:00am for 5 seconds to go from 0 to 60
MPH, you might use 350 horsepower during those 5 seconds. However, if
you then level off at 60 and drive that speed for an hour, your average
over the entire hour may only be something like 60 horsepower.

Power is energy per time. Depending on the extent of the time, you can
consider it "total power" or "average power" over some averaging time.

I did an analysis and explanation of this phenomenon a couple of years
ago. It actually deals with the FFT window in Audition, but it applies
equally to the statistics window, which is based on the FFT.

I think it explains what is going on.

http://81.174.169.10/odds/fftoddity

d

[Mike Rivers]

On Jan 9, 12:36 pm, apa wrote:
Can anyone explain the difference between these two readings in Adobe
Audition's Amplitude Statistics window?

I think the whole concept is bogus, the kind of thing that a
programmer might imagine is useful to an audio engineer. There are no
amps or watts in digital audio (it's only voltage levels that are
digitized) so the program has no clue what the power of anything is,
at least not without some calibration.

I suppose that with a calibrated microphone that puts out a given
voltage proportional to acoustical power it might be meaningful, but
then the program would have to know something about the microphone and
recording chain, which it doesn't.

These RMS "statistics" are just numbers. If you find them helpful in
deciding something that you can't decide by listening, like if one
tune is perceived as louder, softer, or about the same as the adjacent
tune in collection, then by all means make whatever use you can of it.
Otherwise, don't fret about it.

[Peter Larsen[_3_]]

Mike Rivers wrote:

On Jan 9, 12:36 pm, apa wrote:

Can anyone explain the difference between these two readings in Adobe
Audition's Amplitude Statistics window?

I think the whole concept is bogus, the kind of thing that a
programmer might imagine is useful to an audio engineer.

And it happens to so be, bogus or not, it works and is certainly useful for
getting channel balance right to the hundreth of a dB. You may not be able
to hear so small differences without practice .... O;-) ... but it keeps the
boring brain half happy.


Kind regards

Peter Larsen