The BFD was intended , as the name implies, to eliminate mics feedback on PA sound systems. It does that by , first finding the offending freq range and then modifying the gain. Feedbacks usually are a very small/narrow area of the freq spectrum. The BFD can zoom in and only affect that offending freq area; that way the overall freq spectrum (sound) doesn't vary significantly.
So , essentially it is a parametric equalizer.
EDIT: I've never used or played with one. That was more or less the answer an sound engineer gave me 15 years ago when I asked him what the BFD was.
Last edited by JaimeG; 02/06/09 04:25 PM.
