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Section Six: Using GRAPHI-Q Controls
6.1.2. Linking Channel Controls (Two Channel Units)
Two channel GRAPHI-Q units offer a useful and unique feature for linking channel controls. Pulling all
the A channel EQ sliders to the bottom defeats these controls, and applies the B channel settings to the
A channel as well. Now the B channel sliders act as master control for both channels. This applies not
only to the graphic EQ controls, but to controls for the compressor, high and low cut filters, and output
gain. Delay, bypass, and FBX filter controls will remain channel specific (in other words, to bypass the
graphic EQ for the A, you must press “Bypass” for channel A).
6.1.3. The Tweek-n-Peek Feature (Front Panel Models only)
If you’ve been experimenting with the controls on your GRAPHI-
Q front panel, you’ve probably already figured out Sabine’s new
“Tweek-n-Peek” feature. If you’ve ever grabbed a graphic EQ
fader, moved it, and wondered what the “real” setting was, your
prayers have been answered. Tweek-n-Peek shows you the value
of every control on the front panel while you adjust them. As you
move a compressor knob or EQ slider, the value of the setting for
that control will appear in the LED screen that normally displays the
digital delay time. After two seconds of no further adjustment, the
display will revert to the digital delay setting. This means you can
adjust all your controls to a precise, repeatable setting, not just to
a vague knob or fader position. The accuracy of your settings for
all the parameters of your GRAPHI-Q is thus significantly im-
proved. The resolution of front panel graphic EQ fader settings is
½ dB when the range of boost/cut is +6 dB, or 1 dB when the range
of boost/cut is +12 dB. (When using the remote software to control
the EQ faders the resolution is always ½ dB, regardless of range.)
6.2. HIGH CUT/LOW CUT FILTERS
6.2.1. Front Panel Control
These controls are located immediately to the right of the graphic EQ sliders. For the LOW
CUT FILTER, the GRAPHI-Q will attenuate frequencies at and below your knob setting with
a slope of 12 dB per octave. For the HIGH CUT FILTER, frequencies at and above the knob
setting will be attenuated 12 dB per octave. The extreme counterclockwise knob position of
the LOW CUT FILTER and the extreme clockwise position of the HIGH CUT FILTER turn the
filters off. The range of the HIGH CUT FILTER extends from a starting point of 3 KHz to 20
KHz. The range of the LOW CUT FILTER extends from 20 Hz at the bottom to 1 KHz at the
top. The frequency chosen is the point at which attenuation of the filter reaches 3 dB. In other
words, the filter roll-off actually begins just above (for low cut filter) or below (for high cut) the
chosen frequency.
6.3. FEEDBACK CONTROL AND PARAMETRIC EQUALIZATION
Operation of the FBX Feedback Exterminator section of the front panel of your GRAPHI-Q is simple, but
may require a brief explanation for those of you unfamiliar with Sabine FBX products and/or terminology.
Let’s begin by defining a few key terms.
6.3.1. Glossary of Terms
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FEEDBACK describes what happens when a loudspeaker disperses sound back into an amplified
microphone, and at a level sufficient to allow one or more frequencies to ring out of control. Feedback
can occur at any frequency, but is especially painful at mid to high frequencies. The specific
frequencies that feedback in a particular situation depend on the acoustics of the environment, the
placement of the microphone(s) and speaker(s), the response characteristics of the sound system
components, and the volume of amplification. Anyone who has operated a sound system or attended
a conference or a concert is familiar with feedback and its unpleasant consequences!