db volume scaling

[Tim Blechmann]

>>> If they implement the scaling patch (so Tim gets the dB scaling he
>>> wants) but leaves the UI with % marks for a normal user, everyone will
>>> be just fine, since those who understand logarithmic scales will be
>>> able to do the math for a %-dB conversion on the scale Tim has
>>> suggested.  Especially since Tim has already outlined how he did it.
>> well, several people argued _not_ to change the mapping:
>> http://article.gmane.org/gmane.comp.kde.amarok.devel/14535
>> http://article.gmane.org/gmane.comp.kde.amarok.devel/14556
> 
> Actually, I did not argue not to change the mapping.
> 
> I should clarify that when I said I don't like logarithmic sliders, I
> meant ones that show dB values, not ones that behave logarithmically.

then, why didn't you write that before?

> I
> understand the point of them on hifi amplifiers where a particular
> loudness value can be guaranteed, but not on computers where multiple
> sliders (not just in Amarok, but various ALSA mixer values, for
> instance) can be affecting the volume.  I don't see how you can always
> guarantee an absolute value on a normal box with a random built-in sound
> card -- this is why I've been saying that the decibel values you would
> show would be relative, not absolute.

well, the _definition_ of decibel is, that it is relative, not absolute.
decibel can be used as absolute values only by using a point of
reference. db(SPL) for example uses the sound pressure level of the
threshold of human hearing.

> That's (one of the reasons) why I've suggested changing the mapping, but
> not the percentage scale.

both percentage and decibel are relative values by definition. the main
difference is, that percentage is scaled linearly, while decibels are
scaled logarithmically.

you are proposing to use relative/linear units for a logarithmic
mapping, while you can use relative/logarithmic units for it ... now,
what is more confusing for a user?

best, tim

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

Which is more musical, a truck passing by a factory or a truck passing
by a music school?
  John Cage

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