[LAU] Pro Audio? OT rant.

Fons Adriaensen fons at linuxaudio.org
Sun Dec 30 14:12:06 UTC 2012

On Mon, Dec 31, 2012 at 12:54:07AM +1300, Chris Bannister wrote:
> On Sun, Dec 30, 2012 at 12:36:45AM +0100, Jörn Nettingsmeier wrote:
> > to summarize, there are two physical constraints, and they are
> > common to analog and digital signals: bandwidth and dynamic range
> > (or, more precisely, signal-to-noise ratio). in both respects,
> > digital systems out-do analog ones easily, by orders of magnitude,
> I tend to think of SNR and dynamic range as two separate things. I look
> at "dynamic range" as the amount of "headroom" available for an
> instruments variation in loudness/softness. Whereas keeping the noise
> level low enough is another kettle of fish.
> Am I misunderstanding something?

No, both terms are ambiguous, as are many others ('power',
'impedance',... ) Usually the context will make it clear
what exactly is meant when they are used.

'Dynamic range' can mean the range of levels a signal takes
(which is more or less your definition if I understand it
correctly), but the same term is also used as meaning 'the
maximum available signal to noise ratio'. 

Also 'signal to noise ratio' can mean an actual value given
some conditions, or the maximum value for a given system.
So both terms could in some cases mean the same thing. 

It's always necesary to understand the context. For example,
in microphone specs you could find a figure called 'signal
to noise ratio'. In that case this is just 94 dB SPL minus
the self noise, by definition. It's the S/N ratio you get
when recording a signal of 94 dB SPL at the mic, assuming 
your preamp doesn't add noise. And it could be unweighted,
or in dB(A), or be measured using the CCIR 468 method, and
those values could be more than 10 dB different.



A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)

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