12 May
2017
12 May
'17
11:47 a.m.
Hi folks,
I'd like to set up sound level monitoring for my office, with periodic
logging. I have a handheld meter but I'm really looking for a way to use
a traditional condenser microphone and USB audio interface to measure
the level with some kind of windowing, and log it periodically to a file
(maybe once per minute). Is there a decent application that can monitor
and log data in this way?
I'm also open to the idea of just recording a WAV file over 24 hours and
doing the analysis afterwards, with periodic readings from the file.
Is my approach reasonable, to set up a microphone and use the gain knob
to calibrate it against the handheld meter?
I don't need amazing accuracy. We've just moved into a large open-plan
office for the first time and it is very noisy (handheld meter says
about 50dB of air handling noise measured at my desk, rising to 60dB
when there is background talking). I want to monitor sound levels
throughout the day to test my theory that people are more noisy in the
afternoon, and to get an overnight control reading with the people gone
and only the air handling and computers running.
Thanks,
Jonathan
--
Jonathan Gazeley
Senior Systems Administrator
IT Services
University of Bristol
12 May
12 May
11:56 p.m.
Am Freitag, den 12.05.2017, 10:47 +0100 schrieb Jonathan Gazeley:
Is there a decent application that can monitor
and log data in this way?
What you describe is pretty much the same stuff I was teached last
weekend...
I don't know what (linux-)program fits best for this task, but I would
also appreciate a hint for doing a DIN-15905-5-compliant measurement on
linux. :)
I'm also open to the idea of just recording a WAV
file over 24 hours
and
doing the analysis afterwards, with periodic readings from the file.
I know a tool called "replaygain". It's used to compute the loudness of
a soundfile. But, actually, this is another task and - as much as I
know - has nothing to do with determine a sound pressure level...
What you need is something that determines an average value of the
sound pressure you're recording in dbFS. Then, you "only" have to know,
what sound pressure level represents 0 dbFS. But if you're talking
about perception, you also need some kind of weighting... Not that
easy...
Is my approach reasonable, to set up a microphone and
use the gain
knob
to calibrate it against the handheld meter?
Could work, if you find a program that works exactly like that handheld
meter. That means: Same weighting, same time periods. There are
standardized weighting and time periods (slow = 1s, fast = 125 ms), so
chance is you could be lucky.
I don't need amazing accuracy.
You won't get much accuracy, anyway, as long as you don't use "class
1"-equipment which costs several thousand euros.
Even with "class 2"- equipment, 3dB is nothing. At least, this is what
my tutor said last weekend.
Greets!
Mitsch
13 May
13 May
11:52 a.m.
On Fri, May 12, 2017 at 11:56:31PM +0200, Michael Jarosch wrote:
Could work, if you find a program that works exactly
like that handheld
meter. That means: Same weighting, same time periods. There are
standardized weighting and time periods (slow = 1s, fast = 125 ms), so
chance is you could be lucky.
Jnoisemeter will provide the exact filters and detector response.
You could probably modify it easily to print out the measured
value (with some calibration offset) so you can log it to a
file.
Ciao,
--
FA
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
4:30 a.m.
Jonathan Gazeley wrote:
Hi folks,
I'd like to set up sound level monitoring for my office, with periodic
logging. I have a handheld meter but I'm really looking for a way to use a
traditional condenser microphone and USB audio interface to measure the
level with some kind of windowing, and log it periodically to a file (maybe
once per minute). Is there a decent application that can monitor and log
data in this way?
I'm also open to the idea of just recording a WAV file over 24 hours and
doing the analysis afterwards, with periodic readings from the file.
Is my approach reasonable, to set up a microphone and use the gain knob to
calibrate it against the handheld meter?
I don't need amazing accuracy. We've just moved into a large open-plan
office for the first time and it is very noisy (handheld meter says about
50dB of air handling noise measured at my desk, rising to 60dB when there is
background talking). I want to monitor sound levels throughout the day to
test my theory that people are more noisy in the afternoon, and to get an
overnight control reading with the people gone and only the air handling and
computers running.
Hi Jonathan,
I think ecasound might be able to serve your purpose.
The way it works is your send the signal through a chain
with the -ev operator, run the engine for a while,
then use the 'cop-status' command, which provides
text output with statistics about the audio that
was processed.
Here's an example of a non-realtime analysis of a .wav file,
omitting some irrelevant messages.
$ ecasound -i tmh.wav -ev -o null -c
ecasound ('h' for help)> start
[engine finishes]
ecasound ('h' for help)> cop-status
### Chain operator status (chainsetup 'untitled-chainsetup') ###
Chain "default":
1. Volume analysis: [1] cumulative-mode 1.000, [2] result-max-multiplier 1.000
Status info:
-- Amplitude statistics --
Pos/neg, count,(%), ch1...n
Pos 3dB: _______0 _______0
Pos 0dB: _______0 _______0
Pos -0.1dB: _______0 ______17
Pos -3dB: _____717 ____3247
Pos -6dB: ___26347 ___58661
Pos -10dB: __206742 __280703
Pos -20dB: _1177971 _1203440
Pos -30dB: _1035427 __988797
Pos -60dB: __754914 __677400
Pos -infdB: __214307 __211396
Neg -infdB: __107059 ___98364
Neg -60dB: __710105 __641269
Neg -30dB: _1030655 __963146
Neg -20dB: _1162815 _1191367
Neg -10dB: __218110 __291908
Neg -6dB: ___27221 ___61362
Neg -3dB: _____250 ____1563
Neg -0.1dB: _______0 _______0
Neg 0dB: _______0 _______0
Neg 3dB: _______0 _______0
Total.....: _6672640 _6672640
(audiofx) Peak amplitude: pos=0.99997 neg=0.96002.
(audiofx) Max gain without clipping: 1.00003.
(audiofx) -- End of statistics --
HTH,
Joel
Thanks,
Jonathan
--
Jonathan Gazeley
Senior Systems Administrator
IT Services
University of Bristol
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--
Joel Roth
4:34 a.m.
Hi Jonathan,
I found your request actually interesting to play with.
If you use jack, I made a little python script, which only requires you to
download and compile a small program, jack-peak, that Robin Gaerus wrote a
couple of years ago.
You can find it here: http://gareus.org/gitweb/?p=jack-peak.git;a=tree
Just download the tar or zip file, unpack it and type make. It might give
you some erros, but don't worry: if a "jack-peak" file (without any
extension) is created, it means that the build process was successful.
Then, just use the attached "meter.py" script, put it anywere you want,
then copy that jack-peak compiled file in the same path, then run
./meter.py -c 1
this will just create a single input port, without jack connection, and
will print the output at the default delay rate (100ms).
For example, this command line will record the value every second, connect
to the first system audio input and save the data to the file "peaks.txt"
./meter.py -d 1000 -f peaks.txt system:capture_1
By default, the value is a float linear (3 digits after decimal point),
from 0 to 1, you can use a custom integer scale, eg from 0 to 1000.
To stop recording, just hit ctrl+c.
For more options, look at the help documentation:
./meter.py -h
I'm actually thinking about converting it to a pure python script, by
including jack-python bindings and supporting alsa too, but right now I'm
in the middle of another project and I don't have much time for that right
now.
Anyway, let me know if this suits your needs.
PS: Robin's program can be used even without this script, but you need to
forward its output to a file and then parse every line, since it just
rewrites the lines everytime the data is analyzed, which results in an
unreadable output or file.
Cheers,
MaurizioB
2017-05-12 11:47 GMT+02:00 Jonathan Gazeley <Jonathan.Gazeley(a)bristol.ac.uk>
:
Hi folks,
I'd like to set up sound level monitoring for my office, with periodic
logging. I have a handheld meter but I'm really looking for a way to use a
traditional condenser microphone and USB audio interface to measure the
level with some kind of windowing, and log it periodically to a file (maybe
once per minute). Is there a decent application that can monitor and log
data in this way?
I'm also open to the idea of just recording a WAV file over 24 hours and
doing the analysis afterwards, with periodic readings from the file.
Is my approach reasonable, to set up a microphone and use the gain knob to
calibrate it against the handheld meter?
I don't need amazing accuracy. We've just moved into a large open-plan
office for the first time and it is very noisy (handheld meter says about
50dB of air handling noise measured at my desk, rising to 60dB when there
is background talking). I want to monitor sound levels throughout the day
to test my theory that people are more noisy in the afternoon, and to get
an overnight control reading with the people gone and only the air handling
and computers running.
Thanks,
Jonathan
--
Jonathan Gazeley
Senior Systems Administrator
IT Services
University of Bristol
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user(a)lists.linuxaudio.org
http://lists.linuxaudio.org/listinfo/linux-audio-user
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http://www.jidesk.net
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4 comments
5 participants
participants (5)
-
Fons Adriaensen -
Joel Roth -
Jonathan Gazeley -
Maurizio Berti -
Michael Jarosch