PM123's Logarithmic Volume Control Plug-in (LOGVOLUM)

This filter plug-in compensates for non-natural linear mixer controls of cheap sound devices and give the volume bar of PM123 a nearly logarithmic characteristic.

You should not use this plug-in if your sound card already has a mixer with a logarithmic characteristic. You may check what kind of device you have with a simple test: Turn PM123's volume slider from maximum down to 50% while playing. If the volume decreases only a bit, you have a linear control and you should activate this plug-in.

Technical details

Volume responseResponse of the PM123 volume control

X-axis: relative position of the volume slider [%]
Y-axis: gain [dB]
The red line is the response function with the correction.
The green line is the response function of usual sound devices without this plug-in.

Instead of an exponential function the plug-in uses the polynomial:
y = x / (1 + sqrt(10) * (1 - x))
with x and y in the range [0,1] for the transformation. This gives an approximately exponential function with a usable dynamic range of almost 30 dB while keeping the zero point at -∞ dB.