Fuzzmeasure / OS X is good for producing graphs, sweep measurements and it also
has a differential mode to e.g show "before" and "after" material testing.
Natural pink noise and low frequencies are handy when testing mics but
unfortunately that cannot be turned on and off on demand :)
- Also placement of the mic will cause its own coloration, the back wall of the
house and
overhanging porch in this example:
http://soundcloud.com/urlme/pmhc2p-rolling-thunder
Gianni, Ill visit the anechoic chamber when the traffic dies down (for < 100hz)
and make some 94 dB + silence tests for the MR2 + Sony D50. Mics: EM172 & NT1A
via Rolls P48
BR
Mike.
--- In Gianni Pavan <> wrote:
>
> 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? ¦â? ¦. including waterfalls and
> 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? ¦â?¨`
> >
> > 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 like
> > > pink noise? ¦â?¨`.
> > >
> > > I'm curious to know if you have something to suggest for generating such
> > > kind of wideband noise without a speaker? ¦â?¨`.
> >
> > 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, and
> > 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 speakers
> > 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? ¦Ã degli Studi di Pavia
> Via Taramelli 24, 27100 Pavia
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>
>
>
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