dbx DriveRack PA+ - Manual (Page 22)

AFS Comparison Chart
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 they are
updated according to the current selected mode (Fixed or Live).
Clear Live/All
This parameter clears the filters. If Clear Live is selected, then (if invoked) the live filters
are reset to “0” boost or cut. If Clear All is selected, then (if invoked) all of the filters (fixed
and live) are reset to “0” boost or cut. When either Clear Live or Clear All is selected, the
third parameter row displays “Clear w/ Data Wheel.” If Clear (none) is selected, then nothing
is displayed on this row. When the user moves to this third row and turns the Data Wheel
(when Clear Live or Clear All is selected) then the filter reset is invoked.
Mode - Live or Fixed
When the mode is Fixed, the algorithm updates only the fixed filters. When the mode is
Live, the algorithm updates only the live filters. In FIXED mode, the filters are automatically
assigned to a frequency creating feedback, thus remaining at that frequency until cleared
by the user. Fixed mode is used before the performance without any program, instrument or
vocal input signal. In LIVE mode, the live filters automatically detect and remove feedback
during the performance. When all of the live filters have been used, they begin to round
robin. Essentially this means that the first live filter set is replaced where a new feedback is
detected and notched out. This mode is useful because feedback frequencies may change as
the microphone is moved, and/or as the characteristics of the venue change.
Type - Speech, Low Music, Medium Music and High Music
If Fixed or Live mode is chosen, the text will read “Type.” The options will be Speech, Music
Low, Music Medium and Music High. These types pertain to the Q, sensitivity, and algorithm
type. Values are; Speech (Bandwidth = 1/5 octave and Q=7.25) Music Low (Bandwidth =
1/10 octave and Q=14.5) Music Medium (Bandwidth = 1/20 octave and Q=29) Music High
(Bandwidth = 1/80 octave and Q=116). Note: To guarantee that feedback is suppressed at
lower frequencies, the AFS may place wider notch filters at these lower frequencies (below 700
Hz).
Section 5
Detailed Parameters
18
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