Pre-Crossover Graphic Eq; Advanced Feedback Suppressor - dbx DriveRack User Manual

Section 4 Section 4
4.1 Pre-Crossover
4.2 Feedback Eliminator
DriveRack™ PA User Manual
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Detailed Parameters
The DriveRack™ PA offers complete editing flexibility, by offering in-depth control over every
parameter within each effect module. The following section will provide you with descriptions
and explanations of all parameters within the DriveRack™ PA.
The DriveRack™ PA's Pre-Crossover EQ section may be configured as a single or linkable 28
band graphic EQ.
EQ On/Off
Turns the GEQ on and off.
Flatten/Restore
This parameter either flattens the GEQ or restores the GEQ to the last setting before flattening.
The DriveRack unit allows you to leave the EQ edit window and return without losing the edit-
ed EQ settings.
Frequency (F) 31.5Hz to 16.0kHz
This parameter allows you to select any one the 28 available frequencies.
Gain (G) -12 to +12 dB
This parameter allows you to adjust the level of any one of the 28 bands of the GEQ in .5 dB
increments.
The DriveRack™ PA is the first product in the dbx family to offer the exclusive patent pending
AFS (Advanced Feedback Suppression) feedback elimination module.
when a microphonic signal such as a guitar pickup or microphone is reproduced by an ampli-
fication and is repeatedly picked up in phase. The AFS uses Precision Frequency Detection and
state-of-the-art processing to determine the exact portions of a given frequency of your feed-
back that need to be removed (instead of taking out large sections of your sound). The AFS
module of the DriveRack™ PA allows the user to optimize the elimination of feedback. In the
past, graphic equalizers were used to eliminate feedback from a system. This was an accept-
able method for eliminating feedback, but when this method was precision tested, the result
clearly showed that a single 1/3 octave EQ slider was removing approximately half of the sig-
nal power. With the AFS, the module removes the feedback automatically and the proprietary,
precision AFS filters remove only a fraction of the frequency spectrum. The following diagram
shows AFS as opposed to competing, competitive feedback eliminators and conventional graphic EQs:
AFS On/Off
Turns the AFS module on and off. If AFS is Off, the filters are bypassed, and the algorithm is
halted (the filters are not updated). If AFS is On, the filters are active, and the they are updat-
ed according to the current selected mode (Fixed or Live).
DriveRack
dbx AFS
Conventional Feedback Elimination
Graphic EQ
™
PA
Feedback is caused
®