an 11 band parallel bandpass-filter
at default settings it is pretty much an 11-band graphic eq (mono) [gain 1, q 2.5, pan center]
you can change all relevant parameters for each band individually.
honestly speaking, 11 bands are maybe a bit too many for that, maybe 4 would be better. what can help this are the number boxes on top, that effect all bands simultaneously.
top-line number-boxes are pretty much self-explanatory.
with the menu at bottom, you can change how the 1st frequency slider (top) effects the other frequencies. "default" goes back to standard 11-band distribution.