dbx DriveRack PX Manual - Manual (Page 27)

Section 5 - Detailed Parameters
The DriveRack® PX offers complete editing flexibility, by offering in-depth control over every
parameter within each signal processing module. The following section will provide you with
descriptions and explanations of all parameters within the DriveRack® PX.
5.1 Stereo Input 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 PX unit allows you to leave the EQ edit window and return without
losing the edited 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 0.5 dB
increments.
5.2 AFS (Automatic Feedback Suppression)
Feedback is caused when a microphonic signal such as a guitar pickup or microphone is
reproduced by amplification and is repeatedly picked up by the guitar pickup or microphone in
phase. 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 DriveRack® PX 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
competitive feedback eliminators and conventional graphic EQs. The widest filter shown is a
typical 1/3 octave EQ band. The narrower filter indicates the typical bandwidth of competitors’
filters. The narrowest filter is the dbx AFS filter. The narrow filter results in highly effective
feedback suppression without compromising the sound.
DriveRack
®
PX
Section 5
Detailed Parameters
®