Set average to 0 dB

Computes the average in the frequency range determined by the guideline lower and upper limit. see Guidelines chapter below. The average is then subtracted so the average value will be 0 dB.

This can be useful when EQ-ing a sound system, where the goal is to obtain a flat magnitude frequency response and the absolute level is not important. Using this setting, the deviation from a flat curve is read directly from the plot, since the mean value is 0 dB.