db volume scaling

[Tim Blechmann]

>> i have been writing all over again, that mapping and units are two
>> separate issues:
>> - log vs power law (i.e. linear loudness perception)
>> - dB vs percent
>>
>> of course it is easy to map the range -60dB to 0dB to the scale 0% to
>> 100%, but according to your mail [1] you and the majority of the amarok
>> users dislike logarithmic mappings.
> 
> See the mail I just sent.  I don't dislike logarithmic mappings, and I
> have no idea what various users prefer.  What I dislike are showing dB
> values in the software, because you can't guarantee that that is
> actually the loudness level that the user is hearing (explained in more
> detail in the mail I just sent).

see my previous mail. dB [1] is neither dB(SPL) [2] nor dB(A) [3]. to
quote [2]: `The unit dB (SPL) is often abbreviated to just "dB", which
can give the erroneous impression that a dB is an absolute unit by itself.'

>> as far as the mapping is concerned, i guess i wrote enough about the
>> dynamic range of the human ear. with the power-law based mapping, one
>> can do a good fine-tuning for high volumes, but not for low volumes,
>> while with the logarithmic mapping, the volume resolution is equally
>> well from low to high volumes ...
> 
> Which seems like something we want, right? :-)

great, that we finally agree on this

> That's too bad.  I was really looking forward to your remapping patch.

the patch series is available from my git repository [4]

best, tim

[1] http://en.wikipedia.org/wiki/Decibel
[2] http://en.wikipedia.org/wiki/Sound_pressure#Sound_pressure_level
[3] http://en.wikipedia.org/wiki/A-weighting
[4] http://tim.klingt.org/git?p=amarok.git;a=summary

-- 
tim at klingt.org
http://tim.klingt.org

You don't have to call it music if the term shocks you.
  John Cage

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