Description
Input Gain Control: This controlsetsthe signal level to the equalizer. It is capable of -12dBto +12dBof gain. Its
effect is apparent by viewing the OUTPUT LEVELBAR GRAPH.
EQ Bypass: Thisswitch removesthe graphic equalizersection from the signal path. (SeeBlock diagram on Page
32.) TheBYPASS switch does not, however, affect the INPUT GAIN, or LOW CUT filters.
EQ Bypass LED: Thisred LED lights when the EQ isin bypass mode. Note that bypass mode only effectsthe
graphic equalizer section of the 20 Series EQs. TheINPUTGAIN and and LOWCUT controls remain unaffected
when the EQ is bypassed.
Boost/Cut Range Selection Switch and LEDs: Thisswitch selects which of the two boost/cut rangesthe equalizer
will use, either ±6dBor ±15dB. The red LED lights when the ±15dBrange isselected, and the yellow LED lights
when the ±6dBrange isselected. Note that theBOOST/CUT switch isslightly recessed. Thisisto prevent accidental activation of the switch, possibly causing damage to othersound system components.
Output Level Bar Graph: These four LEDsindicate output level of the equalizer. The red LED is 3dBbelow clipping and is marked as +18dBu. It monitorsthe level at the output of the equalizer after all other processing, including the limiter.
Clip LED: This LED lights whenever any internalsignal level reaches 3dBbelow clipping which may occur when
any of the following happen: 1) the inputsignal is “hotter” than +22dBu, 2) excessive gain is applied by the input
gain control, or 3) excessive boost is applied using the frequency sliders.
Gain Reduction Meter: These four LEDsindicate the amount of gain reduction being induced by the setting of the
PeakPlus™ LIMITERTHRESHOLDcontrol as the signal level from the graphic EQ section exceeds this limiter
threshold setting.
PeakPlus™ Limiter Threshold Control: This control engagesthe PeakPlus™ limiter. Itsetsthe threshold level at
which ∞:1 gain reduction will begin to occur. Its design is borrowed from the patent-pending PeakStopPlus™
Limiter found on the popular dbx 1066 and 1046 compressor/limiters. It is capable of a range of 0dBu through
“OFF” (+24dBu). When the threshold control isset to “OFF”, the limiter is effectively disabled, and no gain reduction will occur.
dbx Type III™ Noise Reduction Switch: The switch engagesthe dbx Type III™ NoiseReduction circuit within
the EQ.
dbx Type III™ Noise Reduction LED: The yellow LED lights when the dbx Type III™ NoiseReduction circuit is
activated via the NOISEREDUCTIONSwitch.
Frequency Band Slider Controls: Each one of these slider potentiometers will boost or cut at its noted frequency
by ±6dBor ±15dB, depending upon the position of theBOOST/CUTRANGE switch. When all the sliders are in
the center detented position the output of the equalizer isflat. The frequency band centers of the 2031 and the 2231
are marked at 1/3rd of an octave intervals on ISO standard spacings, while the frequency band centers of the 2215
are marked at 2/3rds of an octave intervals on ISO standard spacings.
Low Cut Enable Switch: The LOW-CUT switch inserts or removesthe 18dB/octave 40HzBessel low-cut filter
from the signal path. When the LOW-CUT switch is pushed in, the LOW-CUT filter isIN the audio path.