The built-in FlexEQ effect is a parametric equalizer with low and high shelf filters and two independent peak filters. These filters are essentially the same as those of the built-in FilterMax effect; see that page for explanation of the filter types. The main difference is that each of the four filters has fixed filter type and a single stage with nominal 12 dB/octave roll-off.
The most common use of FilterMax follows this pattern:
- Sweeten the low-end of the sound using the low-shelf filter
- Sweeten the high-end using the high-shelf filter
- Use one or both of the peak filters with negative gain values, to reduce any harsh peaks in the sound.
Note you can combine an instance of FlexEQ with one or more FilterMax instances for more precise control.