dbx DriveRack VENU360 Loudspeaker Management System - Manual (Page 67)

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TIP: You can change the TYPE parameter at any time. 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 SPEECH/MUSIC 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 SPEECH/MUSIC notch filters for the Live filters (providing slightly faster
feedback suppression during the performance).
• FIXED FILTERS [0 - 12]
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, any 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).
TIP: Since it’s not really possible to predict exactly how many Fixed filters you may need, a good setting to start with
is the default setting of 6. If after ringing out the system, you feel you need to squeeze a little more gain out of the
system before feedback, you can increase the FIXED FILTERS setting and run the AFS Wizard again or manually ring
out only the newly added Fixed filters in the AFS menu.
NOTE: If the FIXED FILTERS setting is changed after filters have been set, the filters will be cleared one by one
as you increase or decrease the setting. For example, if you decrease the FIXED FILTERS setting by one, the last
Fixed filter set will be cleared because the Fixed filter will be changed to a Live filter. Likewise, if the FIXED FILTERS
setting is increased by one (and thus the number of Live filters goes down), then the first Live filter set will be cleared.
The Fixed/Live filter allocation is indicated above the graphic in the AFS menu. “F” indicates Fixed filters and “L”
indicates Live filters. A highlighted F or L indicates a filter that is set, or in use.
• LIVE LIFT [OFF, ON]
This parameter turns the LIVE LIFT feature on and off. When turned on, a timer is enabled. Turn LIVE LIFT on when you
want AFS to lift (release) Live filters after a predetermined time set by the LIFT AFTER parameter. Higher fidelity can be
restored to the system by lifting Live filters when they are no longer needed (for example, if a singer steps to the front
of the stage and triggers feedback, setting a Live filter, and then backs off).
• LIFT AFTER [5S - 60M]
When the LIVE LIFT parameter is turned on, this parameter determines how long it will take before AFS will attempt
to remove a set Live filter. The selectable options range from 5S (5 seconds) to 60M (60 minutes). The updated AFS
algorithm in the VENU360 will slowly release Live filters by 3 dB increments to determine if it is safe to remove them.
If it gets to 0 dB and no feedback reoccurs, the filters are completely lifted. If feedback attempts to reappear while
releasing, the filters are once again set and the timer resets. This helps prevent a sudden reoccurrence of blaring
feedback in the event a Live filter is still needed and needs to remain set.
• SENSITIVITY [-6dB - +6dB]
This parameter adjusts the input level feeding the AFS detector and makes AFS more or less prone to mark a signal as
feedback.
When AFS is set to Fixed mode, SENSITIVITY adjusts the feedback level perceived by AFS. For example, setting
SENSITIVITY to +6 will allow AFS to detect the feedback and notch it out more quickly. Conversely, setting
SENSITIVITY to -6 will cause AFS to be a little more hesitant to set a filter on the feedback until it reaches a higher
level.
When AFS is set to Live mode, SENSITIVITY will work the same way as during Fixed mode on pure feedback tones, but
will also affect where AFS draws the line between feedback and music. If you find that AFS is being too hesitant to set