[alsa-devel] wrong decibel data?
superquad.vortex2 at gmail.com
Sat Apr 10 06:25:42 CEST 2010
2010/4/10 Werner Van Belle <werner at yellowcouch.org>
> Raymond Yau wrote:
> > The dynamic range of 16bit audio is 96dB
> > http://en.wikipedia.org/wiki/Dynamic_range
> Yes about that. I always wondered how they come up with 96dB ?
> A perceived doubling of volume is normally assumed to be +3dB,
> (log_10(2)=0.3) which means that if you have 16 bit audio you have 16
> 'doublings', or in essence only 48 dB. Even worse, since the last bit is
> a sign bit, you essentially can only achieve a dynamic range of 45dB !
> Now, I know this is off topic, but I never heard any good explanation
> why CD audio is suddenly 45 dB ? If anybody knows, please share your
> thoughts !
Even when you are using floating point number
Floating point numbers provide a way to trade off signal-to-noise ratio for
an increase in dynamic range. For n bit floating-point numbers, with n-m
bits in the mantissa and m bits in the exponent
DR is still a finite number
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