Crest Audio X-SERIES X 20R - Manual (Page 13)

Front Panel Features
Mono Input channel features are identical for both the X 18R and the X 20R. The X 18R
has 14 Mono inputs and the X 20R has 12 Mono inputs.
Line Input (Mic Pad)
With this switch in the UP position, the input preamp circuit is set up to accept a
mic-level signal. This signal is brought in via the XLR mic-input connector located on
the rear panel. The 1/4" TRS input jack is ignored.
When the switch is depressed, a Pad is inserted into the signal path and the input
preamp circuit is set up to accept a line-level signal from either the XLR mic-input
connector or the 1/4" TRS input jack, both 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 sig-
nal is fed to the preamp when the LINE switch is pressed. Since the TRS signal is
always padded down 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, avoid-
ing overload. When a plug is inserted into the 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. For
best results, use the Solo system to monitor the channel while you set the gain. The
goal is maximum gain without distortion. Both the main LED meters (during Solo)
and the channel’s Level/Peak indicator can be used for adjusting gain.
70 Hz Lo-Cut Filter
This filter reduces or eliminates unwanted low frequencies without substantially
affecting the program material. Quite often, such unwanted low frequencies are
included with mic- or line-input signals. For example, stage rumble or wind can be
picked up through vocal mics. The cut-off frequency of the filter is 70 Hz and the
slope is -18 dB per octave. This type of filter is also referred to as a Hi-pass filter
(HPF). It allows the high-frequencies to pass, but stops the low-frequencies.
Lo Cut Switch
Lo-Cut filter is bypassed.
Lo-Cut filter is on.
Mono Input Channel
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