[alsa-devel] wrong decibel data?

Raymond Yau superquad.vortex2 at gmail.com
Sat Apr 10 01:32:21 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 !
> Wkr,

When referring to measurements of amplitude it is usual to consider the
ratio of the squares of *A*1 (measured amplitude) and *A*0 (reference
amplitude). This is because in most applications power is proportional to
the square of amplitude,

in electrical circuit , dissipated power is typically proportional to the
square of voltage or current

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