multi band soft clipper
Firegain is a 3-band (soft-)clipper / shaper. I have a feeling that this is similar to a "harmonic exciter".
1. Divide the signal into three frequency bands using box-filters.
2. Applies soft clipping to each of the bands.
3. Recombine the signals to create a final signal.
It introduces a small (a few samples) delay depending on the lower frequency.
Freeware by Jonas Norberg