AW: Volume Pedals

["Rainer Thelonius Balthasar Straschill" <rs@moinlabs.de>]

The question here in part is "ten percent of which physical quantity"?

The human ear works in a logarithmic way, which means something like this:

Let's say you have a sound pressure of 1 Pa (just for example). You 
percieve
that as a subjective loudness x.
If you increase the pressure by a factor of two (now you get 2 Pa), you
percieve the loudness to be increased by a certain amount, which we might
call y, so you now "hear" x+y.
If you now increase the pressure by a factor of two again (so you now have 
4
Pa, which is four times your initial amount), you "hear" x+2y.

Which means: to get these "linear volume dependencies", you need a
logarithmic pot in your volume pedal, because your hearing percieves sound
pressure (and also frequency btw) in a logarithmic fashion and so will hear
a logarithmic pot as linear.

        Rainer