&
The GRAPHI-Q allows two stages of filter resetting. You may reset only the Dynamic filters, or you may
elect to reset all (both Fixed and Dynamic).
-
To RESET DYNAMIC FILTERS ONLY, press and hold the RESET button long enough for the
Dynamic filter LEDs to flash three times, then release.
-
To RESET ALL FILTERS, press and hold the RESET button for seven flashes of all the LEDs, then
release.
Note that resetting all filters automatically engages TURBO MODE, which will allow feedback to occur
and be removed more readily, and at a lower volume. “TURBO MODE on” will be indicated by the TURBO
LED (at the right of the front panel) illuminating.
STEP FIVE: SET FIXED FILTERS (Optional)
If you want to change the factory default setting of nine Fixed and three Dynamic FBX filters, press and
hold the SET FIXED button for approximately four seconds. The corresponding LEDs for all filters set
to FIXED will blink four times and turn off. Release the SET FIXED buttons, and the LEDs will begin to
light in sequence. When the LED corresponding to the desired number of fixed filters lights, press the
SET FIXED button again. You’ve successfully set the number of fixed filters. All remaining filters will
automatically default to Dynamic filters—Unless you are setting filters with your computer.
(See Section
Eight)
STEP SIX: SET FBX FILTER WIDTH (Optional)
FBX filters default to a Constant Q width of one-tenth of an octave. Extensive Sabine research has shown
this width to be an ideal setting, wide enough to remove feedback with very little or no effect upon the
rest of the audio program. In some applications (for example, speech-only applications, where audio
quality is not as demanding as in a music program), however, it may be possible to use a wider filter for
more robust feedback elimination.
The GRAPHI-Q allows you to mix filter widths between one-tenth and one-fifth octaves. You may set
all filters to one width, or some filters to tenth-octave and some to fifth-octave. Width selection is
controlled by the button marked “FIFTH OCT” directly below the RESET button. When this button is
pushed and the LED is illuminated, any filters set after that point will be one-fifth octave wide. Pushing
the button again, and switching off the LED, will make any additional filters one-tenth octave wide.
STEP SEVEN: RAISE MASTER GAIN.
First, make sure your GRAPHI-Q is not set to bypass the FBX filters (check the Bypass button LED;
it should be off). Then, make sure your power amplifier is turned up and your microphones are turned
on. (Note: If you reset the FBX filters, your GRAPHI-Q will be in TURBO MODE, as indicated by
the front panel TURBO LED. See the cautions below.) Slowly raise the master gain of your mixer
until the first feedback begins. The FBX will quickly remove the feedback, by setting the first filter and
lighting the first filter LED. Continue to raise the gain slowly. Try to avoid making two or more frequencies
feed back at the same time, which sometimes happens if the gain is too high. As new frequencies feed
back, new filters will be placed, as indicated by consecutive filter LEDs lighting up. (Note: sometimes
the same frequency will feed back a second time, and an earlier filter will notch more deeply. When this
happens, the original LED indicating this frequency will blink, showing it to be the most recently active
filter.) Repeat this procedure until one of two things happens:
1.
All of the Fixed filters and at least the first Dynamic filter are set. This will automatically turn TURBO
MODE off (LED will turn off to indicate this), or...
2.
You’ve set as many filters as you need or want, even though you haven’t used them all. Press LOCK
FIXED to prevent any more Fixed filters from setting, or any of the set Fixed filters from notching
more deeply. Pressing LOCK FIXED also exits TURBO MODE.
Section Six: Using GRAPHI-Q Controls
