dbx DriveRack 220i User Manual

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dbx DriveRack 220i User Manual Manual pdf 22 page image

Detailed Parameters®14Section 3 220iDriveRack™ User ManualLevel (2-8) -12 to 12 dBSets 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/OctaveSets the slope of the high shelf parametric EQ.Level 9 -12 to 12 dBSets the overall gain of the high shelf parametricThe 220i offers the exclusive patent pending AFS (Advanced Feedback Suppression) feedbackelimination module. Feedback is caused when a microphonic signal such as a guitar pickup ormicrophone is reproduced by an amplification and is repeatedly picked up in phase. The AFSuses Precision Frequency Detection and state-of-the-art processing to determine the exact por-tions of a given frequency of your feedback that need to be removed (instead of taking outlarge sections of your sound). The AFS module of the 220i allows the user to optimize the elim-ination of feedback. In the past, graphic equalizers were used to eliminate feedback from asystem. This was an acceptable method for eliminating feedback, but when this method wasprecision tested, the result clearly showed that a single 1/3 octave EQ slider was removingapproximately half of the signal power. With the AFS, the module removes the feedback auto-matically and the proprietary, precision AFS filters remove only a fraction of the frequency spec-trum. The following diagram shows AFS as opposed to competing, competitive feedback elimina-tors and conventional graphic EQs:AFS On/OffTurns the AFS module on and off. If AFS is Off, the filters are bypassed, and the algorithm ishalted (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).3.3 - Advanced Feedback Suppression