SECTION FIVE ? HOW TO USE FBX FEATURES
5.1. Input / Output Level Switches
Use the two-position switches on the back panel of your FBX1200 / FBX2400 to compensate for input level or output level
requirements. NOTE: For unity gain (recommended), set the channel's input & output level switches to the same setting.
5.1.1. Setting Levels: Set both Input & Output switches the same for Unity Gain
POSITIONINPUT LEVEL SWITCHESOUTPUT LEVEL SWITCHES
Accepts low level input up to +6 dBUOutputs at low level (for insert points or low level devices). See Section 2.3 &
OUT
INAccepts high level input up to +24 dBUOutputs at high level (for most line-level devices). See Section 2.1 & 2.2 for
5.2. FBX Filter Control
5.2.1. Selecting Filter Width
If you?re using the FBX for a music application, the standard 1/10-octave constant ?Q? filter is most effective. However, in
spoken word applications, such as lectures or teleconferencing, we recommend using the wider 1/5-octave filter for more
robust feedback control. You may enable the 1/5-octave filters by pressing the FIFTH OCTAVE button, and the built-in LED will
light. Only filters set after pressing the button in will be 1/5-octave. Press the button again to set subsequent filters to standard
1/10-octave filters.
5.2.2. Setting Number of Fixed vs. Dynamic Filters
To change the number of Fixed filters from the factory default of 9 Fixed and 3 Dynamic per channel, push the READY button
for 4 seconds. The filters LEDs will flash 4 times and then go out. Release the READY button, and the LEDs will begin to light
in sequence. When the LED corresponding to the desired number of Fixed filters lights, press the READY button again.
IMPORTANT TIP: You can mix 1/10- and 1/5-octave filters in the same channel. If you have an especially bad feedback
problem, try making the first few filters 1/5-octave filters.
5.2.3. Resetting FBX Filters
All FBX filters: To reset all FBX filters, follow the directions in Section 4.2.
Dynamic FBX filters only: To reset only Dynamic filters, press RESET DY-
Dynamic FBX filters: Factory default of 3 Dynamic fil-
NAMICS until the current Dynamic filter LEDs flash and then turn off. Re-ters flashing just before reset.
lease the button.
5.2.4. Dynamic Filter Timer
The Dynamic Filter Timer, when enabled, automatically resets Dynamic filters after a user-selected time has passed (refer to
Timer Settings chart at right).
5.2.4.1. Set the Dynamic FilterTIMER SETTINGS
Timer
Off
1. Press and hold the RESET
Current Dynamic Timer (disabled) setting being indicated on third flash.
DYNAMICS button. The Dy-1 min.
namic LEDs flash twice and reset. Continue holding the button and the current Dynamic
Filter Timer setting will flash twice (filter LEDs 1-5, see Filter Timer Chart at right).5 min.
2. Release the RESET DYNAMICS button and filter LEDs 1-5 will cycle through the possible30 min.
timer settings.
60 min.
3. Press RESET DYNAMICS again at the desired timer setting. LEDs will flash twice
(including filter LEDs indicating the current timer setting). Your Dynamic Filter Timer is
now set. The timer starts individually for each Dynamic filter.
5.3. Important Operating Considerations
5.3.1. Power-Off Memory
The FBX stores the positions and depths of the filters in nonvolatile internal memory when the unit is turned off or during a
power failure. The unit will return all filters to their previous frequencies and depths when it is turned back on.
5.3.2. Bypass Mode
The FBX has a true power-off bypass. The signal is unaffected in Bypass mode even if the unit is turned off. Note that if a
combination of balanced and unbalanced inputs and outputs is used, the signal may be disconnected or attenuated in Bypass.
5.3.3. Setup Mode
NOTE: Setup mode is for pre-performance audio setup only, and will cause distortion in your audio program if left
on during performance. You must follow the setup procedure outlined in the previous section, and do not play program
during Setup mode. Otherwise the FBX will clip and filters may be set improperly. (Clip level is set to the lowest level so the
feedback clips quickly; therefore, your program will also be clipped in setup mode. Be sure a dynamic filter is set, and if one
isn?t, press the READY button before your program begins.) You?ll know the FBX1200 / FBX2400 is in setup mode when
the SETUP button is lit. NOTE: You can manually override Setup mode if necessary.
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ACEC
