Filter
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Getting Started
®
10
Section 1
DriveRack
™
ton and the display will read:
• You will now use the <DATA> wheel to select the number of fixed filters. This will range from
values 0-12. The total number of filters will stay at 12, and the number of live filters will be =
Total Num Filters – Num Fixed. Live and Fixed filter types differ in that FIXED mode filters are
automatically assigned to a frequency creating feedback, thus remaining at that frequency until
cleared by the user. In LIVE mode, live filters automatically detect and remove feedback fre-
quencies in the presence of audio (music or speech). When all of the live filters have been
used, they begin to round robin. Essentially this means that the first filter set is replaced where
a new feedback is detected and notched out. This mode is useful because feedback frequen-
cies may change as the microphone is moved, and/or as the characteristics of the venue
change.
• At this page, you will now select the number of fixed filter. Once the desired fixed number
of filters has been selected, press the <NEXT PG> button and the display will read:
The Fixed/Live filter usage will be indicated at the bottom of each page of the feedback elimina-
tion effect. ‘F’ indicates an available fixed filter, and ‘L’ indicates an available live filter. A blocked
out F or L indicates a filter that is set, or in use. Once the desired number has been selected, press
the <NEXT PG> and the display will read:
• These types pertain to the Q, sensitivity, and algorithm type. The filter is established by using
the formula: Q= Freq divided by Bandwidth. This means that a higher Q will produce a fil-
ter that is more narrow. Values are: Speech (Bandwidth = 1/5 octave and Q=7.25) Music
Low (Narrow notch filter, Bandwidth = 1/10 octave and Q=14.5), Music Medium (Very
Narrow notch filter, Bandwidth = 1/20 octave and Q=29) Music High (Ultra Narrow notch fil-
ter, Bandwidth = 1/80 octave and Q=116). To guarantee that feedback is suppressed at
lower frequencies, the AFS may place wider notch filters at these lower frequencies (below
700 Hz). Once the desired fixed type has been selected, press the <NEXT PG> button and
the display will read:
Select fixed type
> Speech
A B
Select number
of fixed filters. 6
F F F F F F L L L L L L
A B
Select total number
of AFS filters. 12
F F F F F F L L L L L L
A B