Dear Dan, I agree with the method you suggest, however my willing is to
have a smooth noise to easily see in real-time the coloration of mics and
variable mounting options.
I'll do some tests with different sources=E2=80=A6. including waterfalls an=
d
showers.
Gianni
2013/8/9 Dan Dugan <>
> **
>
>
> > I'm willing to evaluate the "color" given to recorded sound by
> > different microphones and by the various types of baffles, windscreens,
> and
> > mounting options=E2=88=91
>
> An excellent and very useful project.
>
>
> > I suppose the best way is to record a white noise,
> > however I would have something really "white", not colored by a speaker=
.
> Or
> > at least something with very wide and smooth spectrum, even falling lik=
e
> > pink noise=E2=88=91.
> >
> > I'm curious to know if you have something to suggest for generating suc=
h
> > kind of wideband noise without a speaker=E2=88=91.
>
> I did a test of a home-made windscreen at a waterfall. Recordings with
> windscreen on and off, then compared the spectra. It's the difference you
> care about, not the flatness of the stimulus.
>
> Proceeding from that, one can put pink (not white) noise on a speaker, an=
d
> record with and without the windscreen or baffle. Then make analyses of
> each recording and subtract one curve (naked is the reference) from the
> other. It doesn't really matter that the speaker's output looks awful on
> the analyzer (they all do).
>
> Now that test will give you the windscreen attenuation or baffle
> coloration for one angle of incidence only. I think it's really in the
> diffuse environmental noise that one hears the coloration of a mic rig.
>
> In my lab I have a set of surround near monitors, and a set of distant
> "theater" monitors. I have a Pro Tools session that I call up for mic
> calibration tests that puts uncorrelated* pink noise into all ten speaker=
s
> at calibrated levels so that each speaker contributes equal SPL at the
> measuring location.
>
> In the field I hear a definite wide-band boost of around 3 dB around 250
> Hz with my Jecklin disk. This reminds me I should measure that.
>
> -Dan
>
> * Made by recording a pink noise generator for ten minutes, then slicing
> it up into a one-minute segment for each track. I loop the 10-track
> one-minute playback.
>
>
>
--
Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
Universit=C3=A0 degli Studi di Pavia
Via Taramelli 24, 27100 Pavia
http://www.unipv.it/cibra
http://mammiferimarini.unipv.it
"While a picture is worth a thousand words, a
sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
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