Operator Manual

246 Chapter 30: Input Channels
PRO2 Live Audio System
Owner’s Manual
5 SLOPE switch
(digital trim only)
Selects the low pass filter. Where, switch on
(illuminated) = 12dB slope and switch off = 6dB
slope.
6 stage box control
knob
Adjusts the input gain of the remote amplifier in 5dB
steps, ranging from -5dB to +40dB. Note that the
stage box control knob on the control surface will
only adjust the gain currently selected to the GUI
input channel strip, that is, stage box or digital trim.
7 CHECK switch
(stage box only)
Monitors the mic amp input after the 30Hz filter, but
before any further processing. (The 30Hz subsonic
filter switch accesses the high pass filter on DL431
Mic Splitter when connected to a PRO2. In this case,
the gain steps would be 2.5dB from -2.5dB to
+45dB.)
8 30Hz subsonic
filter switch
Acts on remote amplifier (mic splitter) to remove very
low frequencies in the audio signal — usually caused
by noise on stage. This avoids wasting valuable
headroom trying to digitise it.
9 low pass control
knob (digital trim
only)
Adjusts frequency of low pass filter in the range 2kHz
to 20kHz.
10 Low pass filter
switch /[IN]
(digital trim only)
Activates low pass filter in the input channel signal
path before the insert points and EQ.
11 High pass filter
switch /[IN]
(digital trim only)
Activates high pass filter in the input channel signal
path before the insert points and EQ.
12 high pass control
knob (digital trim
only)
Adjusts frequency of high pass filter in the range
10Hz to 400Hz.
13
Phase switch
Applies a 180° inversion of the input signal polarity
within the input amplifier, such that channel signal
will have opposite polarity to the input signal.
This is used to correct input signal phase problems
when trying to sum signals that are 180° out of
phase. For example, where two mics are facing each
other when using a mic on both the top and bottom of
a snare drum. Ordinarily, the two mics would be out
of phase - causing cancellation when the control
centre sums the two signals into the output.
Reversing the phase of one signal causes the mics to
have the same phase, thus avoiding cancellation.
14 Gain trim (digital
trim) control knob
Applies continuous trim adjustment (small digital
steps) of the input signal level in the range –40dB to
+20dB. Gives a further 60dB of fine adjustment
(DSP) on top of the remote amplifier gain setting.
This control knob on the input fast strips can be
controlling stage box gain, digital trim or delay,
depending on the current state of the swap.
15 Graph Shows the effects of currently applied filter.
Item Control Function