In graphic editors, contrast is a measure of the distribution of luminosity levels. This leads graphic editors to be able to propose “auto-contrast” functions, supposedly using an ideal spread of levels. Can we do the same in audio? An intuitive equivalent of optimal contrast in audio would be a sound for which all frequencies are equally loud.
Profile EQ does real-time spectral matching to an optimal target designed from psychoacoustic studies. The plugin looks complex, but it’s actually much simpler to use than a traditional EQ.