Yes, Bruce. As "about right" as possible. :-)
There are also psycho acoustical factors: If you have a noisy
microphone, mic "hiss" / handling noise / wind noise, you are likely
to get used to these limits and not even try to record some distant
sounds. When you have all such factors optimized, you are likely to
set new limits and try to record more difficult sounds, and face new
problems.
You know.
Such factors are mostly very unconscious and may cause big trouble
for a recordist, constantly bothering about his recordings and trying
to improve his gears.
Klas.
At 18:01 2013-05-24, you wrote:
>Thanks for the responses, this is very helpful. Just to make sure
>I'm understanding all of this, let me know if I have this right.
>When looking at microphone-recorder combinations, the noise floor is
>determined by the noisiest element. But when recording natural
>sounds, the background noise might or might not be the determining
>factor in the noise floor. In a situation like the aspen leaves, the
>noise would cover the spectrum and drown out any contribution of
>microphone or recorder self noise, so it becomes the determining
>factor and a better microphone wouldn't improve the recording. In a
>situation where low-frequency sounds are the main contributors to
>the background noise, the microphone or recorder self noise would
>still be heard over the top of this, so a better microphone could
>potentially improve the recording (if it is the determining factor
>in the microphone-recorder noise floor).
>
>Is that about right?
>
>Thanks,
>
>Bruce
>
>--- In wrote:
> >
> >
> > >> For me, noise masking is an academic dead end. I understand,
> from the principles of 'data reduced' audio storage formats, that
> there are psychoacustic factors that can be bundled up into
> theoretical sumations of reproduction perception.=C2 I get the idea
> that we can be fooled.
> > >>
> > >> I also get the idea that I'm sick and fed up of being fooled, too.
> > >
> > > You are not being "fooled" unless you think your ears are fooling you=
.
> > >
> > >> If you can hear it, it noise.
> > >
> > > If you can hear it, it's sound. If you don't want to hear it,
> it's noise.
> > >
> > >> The fact that there are other noises in the spectrum, doesn't
> mask anything. It's additive. If an orchestra of "noises" played
> together, would you ignore all but the loudest=C2 component ?
> > >>
> > >> I don't think so.
> > >
> > > But your ear-brain axis does "think" so. Masking exists as an
> empirical fact. In this case your intuition is wrong.
> >
> >
> >
> > Robin,
> >
> > Please may I add to your excellent reply? Noise is just part of hearing
> > sounds. Listen out in a quiet place and what can you hear? Your own
> > breathing for a start. That's part of your "self noise".
> >
> > "Self noise" sounds nice and technical but it is only noise from
> one part of
> > the recording chain.
> >
> > Any noise rating requires a defined threshold level in comparison.
> >
> > The fundamental acoustic noise threshhold level is the noise
> produced by the
> > vibration of air molecules. "Excess noise" is the level of the apparent
> > noise above thermal noise. Now comes the snag - thermal noise rises wit=
h
> > frequency at 3dB per octave, and our ears hear low level noise
> approximately
> > according to the A-weighting or IT-U 468 curves. The best field
> mics can do
> > is 10dB to 13dB weighted excess noise above thermal noise.
> >
> > Unless properly defined, this is not related to "self noise".
> >
> > On a "perfect" mic, the excess noise would be 3dBs, because there is
> > vibrating air on both sides of the diaphragm. B&K boast of an
> > instrumentation mic with 5dB excess noise, but it would be unsuitable f=
or
> > general use, even if you could afford one.
> >
> > There is no generally accepted level for weighted thermal noise, so mic
> > manufacturers often use 0dBSPL as a reference which is virtually
> meaningless
> > without a stated weighting.
> >
> > Without weighting, noise values of the pro quality mics would still loo=
k
> > horrendous on paper because of the 3dB per octave slope, but we use the=
m
> > happily. In practice, even in quiet locations, You can't hear low
> level low
> > frequency mic noise on a "good" mic. "Mic hiss" is what to listen out f=
or
> > and you can partly isolate this by my method of putting a mic under a p=
ile
> > of bedclothes.
> >
> > In calm weather I can just hear mic hiss from my old MKH's in my
> woods. Any
> > wind and it is swamped. However I have a de-hiss routine in Audacity wh=
ich
> > works at hiss frequencies only, and is almost undetectable.
> >
> > Going back to my BBC trainee days, we were told that there was only one
> > important job to do when recording sound which is to minimise noise, wh=
ich
> > means first recognising what sounds are wanted and what not.
> Define that and
> > you are an expert. :-)
> >
> > David Brinicombe
> >
>
>
>
>------------------------------------
>
>"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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>
>
>
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