Gianni Pavan wrote
> A great occasion also for those having a phonometer!!
I've tried measuring sound levels with regular recording gear and I'd
appreciate any and all comments, corrections, suggestions, advice on
whether the approach is reasonable and how to improve it.
I proceed in the following way.
1) Record sounds using same microphones, same recorder, same gain settings.
2) Digital transfer to computer.
3) Find the average sample size by doing
(square root[sum from 1 to 1024) (x_i)^2])
4) Average these measures over a number of consecutive blocks (of size
1024) (reporting mean and standard error)
The only evidence I have that this works is based on an experiment I did
taking a standard (digitized) sound (440Hz tone), multiplying its
samples all by a number of different factors and playing it back through
speakers using constant amplifier gain. When I measure these different
sound levels using the above scheme, there's very good correspondence
between the measured level (I actually use a log scale) and the
multiplication factor (on a log scale) used to scale the sound. This
works over a wide range of loudnesses until levels get so low that the
fan of my computer contributes significantly to the sound levels in the
room relative to the playback.
Can I convince anyone that this would substitute for a phonometer?
Thanks!
Steve P
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