Crest Audio X-SERIES X 20R - Manual (Page 23)

Front Panel Features
The Stereo Input channel features are very similar to the Mono Input channels. The X 18R has 2 Stereo inputs,
and the X 20R has and 4 Stereo inputs. On both models, the Stereo inputs are
located to the left of the master
section, and to the right of the Mono inputs. They can be treated as Mono/or Stereo input channels
depending on the position of the SUM INPUTS switch.
Str Line In (Mic Pad)
With this switch in the UP position, the input preamp circuits are set up to accept mic-level
signals. These signals are brought in via the XLR mic-input connectors located on the rear
panel. The 1/4" TRS input jacks are ignored.
When the switch is depressed, a Pad is inserted into each of the signal paths and the input
preamp circuits are capable of accepting line-level signals from either the XLR mic-input con-
nectors or the 1/4" TRS input jacks located on the rear panel. The XLR signal is normaled to
the 1/4” TRS jack. If nothing is plugged into the TRS jack, the XLR signal is fed to the preamp
when the LINE switch is pressed. Since the TRS signal is always padded by 26 dB, this feature
allows the LINE switch to act as a PAD switch for bringing very hot microphone signals
down to a controllable level, avoiding overload. When a plug is inserted into a 1/4" TRS input
jack, the XLR mic-input signal is disconnected and the signal present on the 1/4” plug is fed
to the preamp. If plugs are inserted into both the XLR and TRS jacks, this switch acts as an
input selector switch between the two jacks.
Gain
The Input gain control is used to establish proper gain structure in the channel. The
GAIN control affects both the Left and Right input signals. For best results, use the Solo sys-
tem to monitor the channel while you set the gain. The goal is maximum gain without distor-
tion. Both the main LED meters (during Solo) and the channel’s Level/Peak indicator can be
used for adjusting gain.
SUM Inputs
By summing the inputs, a stereo input channel can be used as a mono input channel. The
channel functions as a stereo input; left input signals feed the left side of the Stereo channel
and right inputs feed the right side.
If signals are applied to both the Left and Right input jacks, they will be summed together as
a mono signal and fed to both sides of the Stereo channel. This sum-point is directly after the
input preamps. If a signal is applied to just one of the input jacks and this switch is pressed,
that lone signal will feed both sides of the channel and it will be treated as a mono signal
throughout the mixer.
Stereo Input Channel
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