dbx AFS224 Manual - Manual (Page 18)

14 AFS™ 224 User Manual
AFS
™
224
Fixed Mode
The AFS 224 offers two main modes of operation: Fixed Mode and Live Mode. Fixed Mode is used to
detect and remove feedback problems in the system due to microphone placement, room modes, etc..
Once set, these filters are stored in the AFS 224 (even after a power cycle) and are not removed until
cleared by the user. The AFS 224 can be put into Fixed Mode by pressing the button until it
lights green. When all Fixed filters have been used, the button will flash green indicating there
are no more Fixed filters available.
Ringing out a system
Fixed filters are set before a performance in a process called “ringing out a system”. This is done after all
other system EQ’ing has been performed. See the “Quick Start” section of this manual for information
regarding ringing out a system.
Using Types in Fixed Mode
The AFS 224 offers several feedback suppression types. These are Speech, Music Low, Music Medium and
Music High. The selected type controls the width of the notch filter used to remove the feedback. Music
High uses very narrow notch filters minimizing the effect on the music. The Speech type uses much wider
notch filters allowing the AFS 224 to work faster. See “Type” in the “Front Panel” section of this manual
for further information.
AFS 224 Filter Q's
Anlg Freq Response.at2
Speech - 1/5th Octave
Music Low - 1/10th Octave
Music Med - 1/20th Octave
Music High - 1/80th Octave
-9
+3
-8
-7
-6
-5
-4
-3
-2
-1
-0
+1
+2
d
B
u
-9
+3
-8
-7
-6
-5
-4
-3
-2
-1
-0
+1
+2
d
B
u
700 1.2k 750 820 850 900 .95k 1k
Hz
During the filter setting process, the filter type can be changed by pressing the channel’s button.
This will change the filter type for the next filter and will not change existing filters. When all Fixed filters
have been used, new feedback occurrences will not be removed. Pressing the button will
place the AFS 224 into Live Mode (indicated by the button(s) lighting Red) and feedback will
continue to be removed. If more Fixed filters are needed, reallocate more filters by following the steps in
Setup Mode or clear the filters (see the “Clearing Filters” section) by pressing and holding the
button until all the Filter LED’s blink and repeat the ring out procedure with a wider filter type.
WARNINg! Ensure the system’s gain is reduced before clearing filters.
Operation