13 May
2017
13 May
'17
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