Change sound volume in dB, not in percent

[scytho]

Sound volume in Mate changes in steps of 5% (Percent of what? I cannot figure that out.), at least when you use the mouse wheel on the volume applet in the panel. That leads to steps from 1,34dB (100% → 95%) up to 18,07dB (10% → 5%), which are inconsistent and too big. Volume should be changed by the same value in dB. That way, the human ear perceives each step (each of x dB) as the same amount of change in volume/loudness. I guess steps of 0,5dB would be ideal, as for most signals that should be about the minimal change the human ear can detect. It would be very nice to have the possibility to change it, though.

mate-desktop/mate-desktop#223
mate-desktop/mate-panel#1445 (comment)