Rockbox mail archiveSubject: Re: rockbox-recorder-20061122 - volume representation messed up
Re: rockbox-recorder-20061122 - volume representation messed up
From: Philipp Pertermann <perterm_at_vce.de>
Date: Tue, 28 Nov 2006 10:51:01 +0100
> I don't understand why 0dB doesn't mean `dead silence'. I mean, that's
> what decibels are, right, a unit of sound intensity?
In audio gear decibel is used to describe the _amplification_ of the
system. It is not a unit of sound intensity. 0 db means unity gain, the
input signal is not altered - neither amplified nor muted. In digital
audio gear the input signal is the sample data stream.
We can not amplify this input signal because we can not represent any
values that exceeds the value range of our sample data words (limited
bits per sample value). In digital domain we usually talk about dbfs
(decibel full scale). This full scale is the maximal signal swing that
can be represented with sample data words of limited bit size.
Received on 2006-11-28