USAudio wrote:
> Pat Farrell;223026 Wrote:
>> It is true that if you cut the volume to 25% (down 12 dB) you take a 16
>> bit signal and now have only 14 bits that are meaningful. But the same
>> impact happens in analog.
> Thanks Pat, that is what I was clumsily trying to convey but wasn't
> aware there was the same impact in analog.
Yes, its fairly easy to understand. when you attenuate a signal, the
signal goes down, but the noise stays constant. So you lose the stuff
that makes the signal stand out of the noise.
Technically:
Say you have a signal with 100dB of signal and 30dB of noise.
SNR is 20 log10(S/n)
where S is signal and n is noise, in volts, or volume.
SNR == 20 log10( 100/30)
== 20 log10 (3.33)
== 20 * 0.5228
== 10.45
Crank the sound down to 50% of what it was so 100dB becomes 94 dB.
SNR == 20 log10( 94/30)
== 20 log10 (3.133)
== 20 * 0.4960
== 9.920
It is interesting to note that cutting the voltage (which roughly
approximates loudness) in half, reduces the power needed by a factor of
four.
--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html
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