4
Operating Manual -MX-406 Stereo Microphone/Line Mixer
4. FRONT PANEL CONTROLS
4.1 Input Gain
This three position switch sets the operating level
of the microphone and line input preamp. The correspond-
ing switch values -20db, -40dB, and -60dB refer not to
the actual gain, but rather to the expected nominal input
signal strength.
Best signal to noise ratio is obtained with higher
gain settings. It is therefore desirable to set the gain con-
trol as high as possible while still leaving 20dB of head-
room for signal peaks. Line level inputs (1/4" jack) will
likely use a setting of -20dB, while mic inputs generally
require a setting of -40dB for close mic applications, and
-60dB for quieter signals. If a channel's clip LED is blink-
ing, first turn down that channel's level control. If the
clip LED is still flashing, turn down the input gain.
4.2 Clip
Input Clip LEDs are peak sensitive and monitor
all critical points within the input channel. The clip LED
turns on whenever any portion of the audio path within
the input channel reaches a level 3 dB below actual clip-
ping. Clipping in the MX-406 occurs at +20dB.
4.3 Treble/Bass
This concentric knob is used for broad EQ
changes to each input channel. Channel EQ consists of a
high shelf control (treble) at 4KHz, and a 250Hz low shelf
control (bass). EQ boost or cut is ±12dB.
4.4 Aux
The aux send is an additional level control used to
send signal from each input channel to monitors, an effect
unit, or another mix. The aux master output combines all
six channel's aux level signals. The aux control is factory
set to pre-fader, pre-EQ, but can be internally switched to
post-fader, post EQ. To make this change, refer the fol-
lowing procedure to a qualified service technician:
Unplug the unit's AC power cord from the outlet.
Remove the bottom cover which is fastened by seven 6-32
screws. Locate the 3 pin header labeled AUX at the middle
of the back edge of the front portion of the channel cir-
cuit board. Remove the shunt bar from the "Pre" position
indicated on the circuit board legend and place the shunt
on the "Post" position.
4.5 Level and Pan
This concentric knob adjusts the level and stereo
position of each channel. If a channel's level control is
always turned up to 9 or more, try increasing the gain
first. Conversely, if the level control is consistently turned
down to 1 or less, decrease the gain setting first. Re-
member that the gain setting should be set as high as pos-
sible while still allowing 20dB of headroom.
4.6 Stereo Line Input
This control adjusts the level of the RCA jack
stereo line input. It can be used for tape, CD, or DVD
audio inputs, and can also be used for a stereo effect re-
turn. For expanding the channel capacity of the MX-406,
Treble
Bass
C lip
-12
+1 2
8
7
6
1
3
4
0
1 0
5
R
L
8
7
6
1
4
Level
Pan
9
Channel 6
Aux
0
Treble
Bass
C lip
-12
+1 2
7
6
1
3
4
0
1 0
5
R
L
8
7
6
1
4
Level
Pan
9
Channel 5
Aux
0
Treble
Bass
C lip
-12
+1 2
7
6
1
3
4
0
1 0
5
R
L
8
7
6
1
4
Level
Pan
9
Channel 4
Aux
0
Treble
Bass
C lip
-12
+1 2
7
6
1
3
4
0
1 0
5
R
L
8
7
6
1
4
Level
Pan
9
Channel 3
Aux
0
Treble
Bass
C lip
-12
+1 2
7
6
1
3
4
0
1 0
5
R
L
8
7
6
1
4
Level
Pan
9
Channel 2
Aux
0
Treble
Bass
C lip
-12
+1 2
7
6
1
3
4
0
1 0
5
R
L
8
7
6
1
4
Level
Pan
9
Channel 1
Aux
0
-40
-60
-20
-40
-60
-20
-40
-60
-20
-40
-60
-20
-40
-60
-20
-40
-60
-20
Input
(d B)
Input
(d B)
Input
(d B)
Input
(d B)
Input
(d B)
Input
(d B)
8
