Crest Audio X-Four User manual

owners manual
X-Four mixing console

X-Four owner’s manual
block diagram
Σ
OFF
Ø
R
L
1 3
SOLO
OFF
SOLO
AUDIO
ON
MONITOR OUT
SOURCE SELECT
POST / PRE FADER
LR
LR
FROM
SOLO
LOGIC
SCL+
HP
LEVEL
X-Four Block Diagram
SCL-
+10
+10
PEAK
LO MID
Σ Σ Σ Σ Σ Σ Σ
Σ
NO
+10
L
R
2
4
4
1
3

1
2
3
4
5
group p. 41
master p. 57
power supply p. 81
stereo inputs p. 25
mono inputs p. 7
table of contents

X-Four owner’s manual

how to use this manual
conventions
terms
indicators or controls employed on the X-Four console
will appear as: TERMS
tasks
are broken down into steps 1
2
3
warnings
indicators
tips
see
see—references other sections of the manual containing
supplementary information on the current topic or a related issue
Prefered methods.
Helpful hints.
Feature insights.
+
Procedures not to attempt.
Issues or hazards to keep
in mind when operating
the equipment.
a
What to look
for on-screen.
Alerts, indicators, or
prompts that may appear.
®

p. 6
X-Four owner’s manual
mono input module
module panel
legend
block diagram
1

p. 7
mono input module
features
phantom power—+48V
48 volts DC is applied to pins 2 and 3 on the mic-input XLR con-
nector. This option is used with condenser microphones and active direct
boxes that require an external DC voltage (phantom power) in order to
operate.
pad
The mic-input signal is attenuated by 15dB to prevent some signals
(e.g. kick drum or lead vocal) from overloading the preamp stage.The pad
is used to bring a hot mic-input signal down to a controllable level.The
15dB pad is not functional when the LINE switch is depressed.
line
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 disabled.
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 locat-
ed on the rear panel.
When a plug is inserted into the 1/4" TRS input jack, the XLR mic-input
connector is disabled.
polarity reverse—ø
This feature is used for correcting or minimizing polarity and phase relat-
ed errors. For example, occasionally a balanced input connection is
reverse-wired before it gets to the mixing console. This can happen in
microphones, or in snake line interfaces. By using the polarity reverse fea-
ture, this type of error can be corrected.
polarity inverted
polarity not inverted
If the channel peak
LED is illuminated,
first try lowering
the input gain control.
Only when this method is
unsuccessful should the pad
switch be engaged.
+
If the 48V phantom
power switch is
engaged, depressing this
switch disconnects phantom
power from the mic input
XLR.
+
1
When similar signals
from different chan-
nels are combined, phase
cancellations can occur.
Reversing the polarity of an
input signal often corrects
such phasing errors.
+
The 48V switch should
not be engaged when
using standard (dynamic)
microphones, or other
sources that do not use
phantom power.
a

p. 8
X-Four owner’s manual
mono input module
module panel
legend
block diagram
1

p. 9
mono input module
features
gain
The Input gain control range is closely related to the status of the PAD
switch and the LINE switch. In order to establish proper gain structure in
the console, input gain settings must be set correctly.
LINE—switch-up PAD—switch-up
15 to 75dB of gain can be added the mic-input signal.
The impedance at the input XLR is 4kΩ.
LINE—switch-up PAD—switch-down
-5 to 55dB of gain can be added to the mic-input signal.
The impedance at the input XLR is 4kΩ.
LINE—switch-down PAD —switch-up or -down
-10 to 45dB of gain can be added the line-input signal.
The impedance at the input XLR and input 1/4" TRS is 20kΩ.
high-pass filter—HPF
Proper use of the high-pass filter reduces or eliminates unwanted low fre-
quencies without substantially affecting the program material. Quite often
such unwanted low frequencies are included with in-coming mic- or line-
input signals. For example, stage rumble or wind can be picked up through
vocal mics.The slope of the high-pass filter is 12dB per octave.
HPF
High-pass filter is on @80 Hz, 12 dB/octave
1
If the channel peak
LED is illuminated,
first try lowering
the input gain control.
Only when this method is
unsuccessful should the pad
switch be engaged.
+

1
p. 10
X-Four owner’s manual
mono input module
module
legend
block diagram panel

p. 11
mono input module
EQ features
Many audio signals coming into the console require some degree of cor-
rective eq in order to be part of a good sounding mix.
The input eq consists of four-bands: high, high-mid, low-mid and low.
The high and low bands have fixed frequencies while the high-mid and low-
mid bands are sweepable, with their higher and lower frequencies over-
lapping adjacent bands.
high frequency—HF
15dB boost and cut at 12kHz.
The boost response is bell-shaped and the cut response is shelving.
high-mid frequency—HM
15dB boost and cut.
Selectable frequency range of 400Hz to 8 kHz.
The response is bell shaped with a fixed Q of 1.5
low-mid frequency—LM
15dB boost and cut
Selectable frequency range of 80Hz to 2 kHz.
The response is bell shaped with a fixed Q of 1.5
low frequency—LF
15dB boost and cut at 80Hz.
The boost response is bell-shaped and the cut response is shelving.
eq on
Equalizer is on. This switch can be used to make A/B comparisons
between "flat" and eq'd signals.
1

1
p. 12
X-Four owner’s manual
mono input module
module panel block diagram

p. 13
mono input module
aux send features
Six auxiliary AUX SENDS are available for creating individual output mixes.
These mixes can be used for driving effects processors, providing monitor
mixes, creating broadcast or alternate sound reinforcement mixes, or
other special requirements.
aux sends 1–6
These knobs adjust the amount of signal sent to the AUX buses.
Unity gain occurs at the zero setting. AUX 6and 8controls pan function
when selected for stereo operation.
aux 1–4, 5/6 pre-fader—PRE
The default signal source for the AUX SENDS is post-fader.These switches
are used for selecting the pre-fader signal for their respective auxes.The
pre-fader signal is derived post-mute and post-eq.
see—internal jumper options
AUX SENDS are post-eq, post-mute, and post-fader.
AUX SENDS are post-eq, post-mute, and pre-fader.
aux stereo 5/6
The default configuration for AUX 5, and 6, are mono, as with AUX 1–4.
In situations where stereo-aux signals are required (such as driving stereo
in-ear monitors or effects processors), this switch reconfigures the AUX
SENDS to operate in stereo by changing the functions of the potentiometers.
AUXES are configured as individual mono sends.
AUXES are configured as level and pan for stereo operation.
1

1
p. 14
X-Four owner’s manual
mono input module
module panel block diagram

p. 15
mono input module
bus assignment features
The Input bus assignment section offers considerable flexibility for creat-
ing what eventually becomes the main output mix. Such features as LCR,
GROUP PAN ON and eight-individual group assignments allow several
approaches to building the desired mix.All assignments are derived post-
fader, post-eq, and post-mute.
left-center-right—LCR
This feature is used to precisely position a signal in a sound system with a
center speaker cluster in addition to left and right clusters.The PAN control
becomes an integral part of how the input-signal is sent to the LEFT,CEN-
TER, and RIGHT outputs.
The post-fader signal is assigned to the LEFT,RIGHT, and MONO/CENTER
buses. Relative amounts of the signal fed to each bus is determined by the
position of the PAN control.
pan control
The pan control positions the signal within the stereo left/right field,
(or between left/center or center/right in LCR mode). The signal must be
assigned as stereo in order for the pan control to have any affect.
see—left-center-right
mute
The Mute switch mutes the channel as well as both pre- and post-
fader AUX SENDS.
write-in label
This label may be written on with a grease-marker, and later wiped clean
with a cloth moistened with isopropyl/rubbing alcohol. Masking tape may
also be placed on this surface, if desired.
1
An internal jumper
can be used to defeat
pre-fader muting.
+

1
p. 16
X-Four owner’s manual
mono input module
module panel block diagram

p. 17
mono input module
bus assignment features
mute
The Mute switch mutes the channel as well as both pre- and post-
fader AUX SENDS.
write-in label
This label may be written on with a grease-marker, and later wiped clean
with a cloth moistened with isopropyl/rubbing alcohol. Masking tape may
also be placed on this surface, if desired.
1

1
p. 18
X-Four owner’s manual
mono input module
module panel block diagram

p. 19
mono input module
level meter features
level meter
Each input includes a five-segment LED meter
for visually monitoring signal levels.This is essential for setting up and main-
taining proper gain structure.
peak indicator—PK
The input signal is monitored at several points throughout the chan-
nel.These points are the mic preamp, the EQ stage and the fader stage.
Overloads at any of these stages will cause the red peak-LED to light.
Then the channel gain should reduced.
signal level LED’s
These three LED's light up at +8—yellow,0—green, and -6 dB—
green. This level range -6 to +8 is the optimum operating range.
Compressed or relatively constant signals should remain close to 0.
signal present indicator—SIG
This green-LED varies in brightness in response to signal levels
between -40 dB and -6 dB.
LED
LED
LED
LED
LED
LED
LED
LED
Occasional flashing of the
peak LED is acceptable,
but frequent flashes indi-
cate that channel levels
must be lowered.
®
1
If the channel peak
LED is illuminated,
first try lowering
the input gain control.
Only when this method is
unsuccessful should the pad
switch be engaged.
+

1
p. 20
X-Four owner’s manual
mono input module
module panel block diagram