db volume scaling

[Jeff Mitchell]

On Thu, 11 Jun 2009 01:55:34 +0200, Tim Blechmann <tim at klingt.org> wrote:
>>>> 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?

Why wasn't I clear before?  Because I didn't realize I wasn't being clear.

>> 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.

Which is my point.  So then how loud is 0dB, if you see it in Amarok? 
-60dB?

It's not really any better measure of the actual loudness of the sound,
only the relative loudness, which is the same thing that a percentage scale
is -- except that according to the results you quoted before (which I
believe), the percentage scale is not accurate, in terms of the way we
actually perceive loudness.

> 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?

Logarithmic.  I think the benefit of remapping would be that users have the
ease of the percent scale while having the actual relative loudness, as
perceived by the human ear, seem to track linearly.

--Jeff