dbx DriveRack 220i - Manual (Page 22)

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220i
DriveRack ® User Manual
Q (2-8) 0.105 to 16.0
Q is adjustable from 0.105 to 16.000
Level (2-8) -12 to 12 dB
Sets the overall level of the selected parametric EQ frequency.
Band 9 Frequency 20 to 20k (High Shelf)
Selects the frequency of the high shelf parametric EQ.
Slope 9 3-12dB/Octave
Sets the slope of the high shelf parametric EQ.
Level 9 -12 to 12 dB
Sets the overall gain of the high shelf parametric
3.3 - Advanced Feedback Suppression
The 220i offers the exclusive patent pending AFS (Advanced Feedback Suppression) feedback
elimination module. Feedback is caused when a microphonic signal such as a guitar pickup or
microphone is reproduced by an amplification 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 feedback that need to be removed (instead of taking out large sections of your sound).
The AFS module of the 220i 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 acceptable 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 signal 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 updated according to
the current selected mode (Fixed or Live).
Detailed Parameters
Section 3