Higher frequencies are normally perceived as louder, which AmpCompA compensates. Following the measurements by Fletcher and Munson, the ANSI standard describes a function for loudness vs. frequency.
Note that this curve is only valid for standardized amplitude. 1
For a simpler but more flexible curve, see AmpComp
Input frequency value. For freq == root, the output is rootAmp.
Root freq relative to which the curve is calculated (usually lowest freq).
Amplitude at the minimum point of the curve (around 2512 Hz).
Amplitude at the root frequency.
freq, the values are not modulatable