Behringer Feedback Destroyer Pro DSP1100P - Manual (Page 12)

12
2.1 Activating/deactivating the filters
In “OF” mode, the corresponding filter is deactivated and can be activated by selecting one of the modes
described below.
2.2 Manual filters / parametric equalizer
The FEEDBACK DESTROYER PRO allows you to freely process any music signals. To raise or lower
specific frequencies in level, you can directly select these frequencies by means of the manual filters (Para-
metric EQ mode). Each filter has the functionality of a fully parametric EQ, i.e. you can set the center
frequency, the quality factor (Q) and the amount of boost/cut (in dB).
2.3 Automatic filters
The FEEDBACK DESTROYER PROs automatic filters operate in two modes: Single-Shot and Auto mode. In
order to find a feedback, the FEEDBACK DESTROYER PRO divides the entire frequency band into 1/60
octave steps (20 Hz to 20 kHz) and determines the respective level of these individual bands. He compares
this value to the level of the entire signal. The difference of these levels determines whether a filter is set. The
FEEDBACK DESTROYER PRO now provides you with the unique possibility to adapt this parameter according
to your own needs. You can edit this feedback sensitivity within a range of -3 dB to -9 dB (in 1 dB steps). The
standard value for this parameter is -6 dB. This value provides an optimal recognition of feedback during most
applications. During e.g. a pure speech transmission, the feedback sensitivity can be lowered to -9 dB. In this
way, the algorithm would recognize and would suppress a feedback even faster. On the other hand a higher
adjustment of the feedback sensitivity (e.g. -3 dB) makes feedback suppression more stable. In addition to
that intended feedbacks (guitars or keyboards) become recognized much more slower.
Filters in Single-Shot mode automatically analyze the music signal to detect feedback frequencies. Having
detected such a frequency, the filter automatically configures its parameter to suppress feedback as efficiently
as possible. As the filter is locked to the detected frequency, this mode is ideally suited to suppress feedback
having a constant frequency. Possible applications are “fixed-position” microphones (e.g. on the drums). After
the filter has adjusted itself automatically, it enters a special Lock mode, which means that although the
frequency remains fixed, the width and depth of the filter are still being adapted to the feedback frequency, i.e.
the width is increased as soon as the feedback frequency begins to shift, and the gain is cut if feedback
prevails. The gain is not reduced to prevent feedback from recurring.
All microphones that are moved during a performance (e.g. vocal mics) very often have varying feedback
frequencies. This type of feedback should be suppressed in Auto mode. As in Single-Shot mode, the filter
automatically selects an ideal setting for feedback suppression. But in Auto mode a locked filter tracks and
suppresses the feedback frequency even as it changes. The optimum frequency is selected automatically and
the filter is set to narrow-band mode so as to influence the music signal as little as possible. If your music
contains wanted feedback elements (e.g. guitar feedback), it is highly probable that these will be suppressed
too in Auto mode, because from a physical point of view it is impossible to distinguish “wanted” from “un-
wanted” feedback. Please read the hints given in section 6.3 to work around this situation.
2.4 Working with programs
In order to store your favorite settings, the FEEDBACK DESTROYER PRO has ten user presets and a default
preset. All operating parameters can be stored, i.e. your programs are recalled in full detail. Owing to state-of-
the-art circuitry, no internal battery is needed, hence the memory contents will not be lost. In the default preset
(display “--”), which serves as a basis for creating your own programs, all filters remain in the parametric mode,
with bandwidth set to 1 octave, a frequency of 500 Hz and 0 dB gain.
2.4.1 Recalling programs
After power-up, the FEEDBACK DESTROYER PROs display reads the number of the preset last used. The
jog wheel allows you to conveniently select the preset of your choice. Turn the rotary control to the left to step
through the programs in descending order. Turn it to the right to increment the programs. The default preset is
located in front of the first program.
+
Please note that the FEEDBACK DESTROYER PRO generally activates the newly selected presets
2. OPERATION