Feedback Prevention - Rebis Audio RA402 Operator's Manual

FEEDBACK PREVENTION

The RA402 can be utilised to prevent acoustic feedback in sound rein-
forcement systems. Set all sections for full cut with narrow bandwidth
and switch them out. Increase system gain until feedback just starts, se-
lect the section which covers the band in which the frequency of oscilla-
tion lies, switch the section in and sweep the frequency control until the
oscillation stops. Now reduce the amount of cut until the feedback starts
again and then back off a little.
This procedure is then repeated at higher system gains, the next three
feedback frequencies being notched out with three remaining sections.
With the great overlap on frequency controls even several close frequen-
cies of oscillation can be counteracted without trouble. It should be not-
ed that an audience will almost certainly alter the resonances in an
auditorium and therefore the anti-feedback technique described here
should be carried out in as near to live situation as possible.