JBL 260 User Manual

Selects the frequency of the high shelf parametric EQ.

Sets the slope of the high shelf parametric EQ.

Sets the overall gain of the high shelf parametric 

The DriveRack 260 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 with 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 DriveRack 260 
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 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: 

 

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).

This parameter clears the filters. If Clear Live is selected, then (if invoked) the live filters are 
reset. If Clear All is selected, then (if invoked) all of the filters are reset. When either Clear Live 
or Clear All is selected, the third parameter row displays “Clear w/ Data Wheel.” If the Clear 
field is blank, then nothing is displayed on this row. To clear filters move the cursor down to 
the ‘Clear w/ Data Wheel’ row, then turn the Data Wheel. ‘Clearing Filters...’ will appear in the 
display.

When the mode is set to Fixed, the algorithm updates only the fixed filters. When the mode is 
set to Live, the algorithm updates only the live filters. In FIXED mode, the system is forced into 
feedback by the user and filters are automatically assigned to a frequency which is