dbx DriveRack PA2 Owner's Manual page 37

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begin to round robin – meaning that if all Live filters have been set and new feedback occurs, the first Live filter set will be
released then re-set at the new feedback frequency location. The Live filters can be set to release after a period of time by
enabling the LIVE LIFT option and adjusting the LIFT AFTER parameter. Note that when you run the AFS Wizard, AFS will
automatically switch between Fixed and Live mode operation behind the scenes.
• [SPEECH, MUSIC/SPEECH, MUSIC]
TYPE
This parameter sets the width and sensitivity of the AFS filters. The available options are:
SPEECH (Constant bandwidth of 11 Hz below 76 Hz, constant Q of 7 at or above 76 Hz)
This option is optimized for speech sound reinforcement, where wider notch filters are less noticeable. Select this
option when using the sound reinforcement system for speech only. With this option selected, notch filters will be
wider, but will provide the fastest, most solid protection against feedback.
MUSIC/SPEECH (Constant bandwidth of 9 Hz below 260 Hz, constant Q of 29 at or above 260 Hz)
This option is optimized for live music sound reinforcement or speech and provides the best all-around protection. It
will provide the best combination of fast feedback suppression and precision, using filters slightly narrower and less
audible than the SPEECH setting, but slightly faster than the MUSIC setting. If you're not sure which setting to use,
select this option.
MUSIC (Constant bandwidth of 8 Hz below 927 Hz, constant Q of 116 at or above 927 Hz)
This option is optimized for live music sound reinforcement and offers the highest level of sonic quality. When this
option is selected, the AFS algorithm will zero in on the offending feedback frequency, while leaving the surrounding
frequencies unscathed. With this option selected, the AFS filters will take slightly longer to set than when using the
MUSIC/SPEECH setting, although the difference in time will be quite negligible, but will be virtually inaudible.
Note:
To guarantee that feedback is suppressed using the minimum number of filters possible, AFS may
automatically widen filters. For example, if you had selected the MUSIC setting and an adjacent frequency is feeding
back, AFS will detect both frequencies, and if they are in close enough proximity, will set a single, wider filter rather than
two narrow filters. Using a single, wider filter rather than two narrow filters will not alter the sonic quality and will ensure
that the maximum number of filters will always be available for use. Automatically adjusted filter widths will never be any
wider than the SPEECH setting.
HiNt:
You can change the TYPE parameter at any time when manually ringing out the system with AFS. This allows
you to use narrow notch filters in combination with wider notch filters. For example, you could set the TYPE parameter
to MUSIC then ring out the system in Fixed mode, switch over to Live mode, then set the TYPE parameter to MUSIC/
SPEECH for the Live filters. This would allow you to use the extremely narrow MUSIC notch filters for the Fixed filters
(providing the best sound quality possible), then use the slightly faster, wider MUSIC/SPEECH notch filters for the Live
filters (providing slightly faster feedback suppression during the performance).
• [0 - 12]
FIXED FILTERS
This parameter sets how many of the AFS filters will be allocated as Fixed filters. After selecting how many filters will be
allocated as Fixed filters, all remaining filters will be allocated as Live filters. There are a total of 12 AFS filters available, so
the simple formula is: Total Filters Available - Selected Number of Fixed Filters = Number of Live Filters. For example, if you
select a FIXED FILTER setting of 8, you will have 4 Live filters available for use (12 - 8 = 4).
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