Channel 3 and 4 controls, U. 4 20d 4-channel mic/line mix er, Gain – MACKIE U.40d User Manual
Page 16: High eq, Mid eq, Low eq, U.420d 4-channel mic/line mixer
16
U.420d 4-Channel Mic/Line Mixer
U.
4
20d 4-Channel Mic/Line Mix
er
Channel 3 and 4 controls
Channel 2 and 3 are identical stereo channels, fed by
the line-level input connectors [2] or the phono-level
inputs [3]. The controls are stereo, and the final output
of each channel is added to the left and right main mix.
These channels are set up with a crossfader, ideal for
DJ work with two turntables. The EQ controls are also
DJ-friendly with a kill position, where each frequency
band can be turned fully off if needed.
The controls are much the same as the mono chan-
nels 1 and 2, but there are enough differences in the
details to justify an extra page or two.
20. GAIN
This knob adjusts the gain of the stereo preamp.
Signals from the line-level input jacks [2] go straight to
the preamp and this control. Phono-level signals enter-
ing the phono inputs [3] are first passed through an
RIAA phono preamplifier to become line-level.
The gain ranges from –14 dB to +14 dB, and it should
be adjusted so that the level set LEDs [10] are on for
about half the time during your performance. This gives
you the best signal-to-noise ratio for the preamp.
21. HIGH EQ
This knob gives your channel signal up to 10 dB of
boost at 4 kHz and above. In the kill position, the high
frequency range above 4 kHz are muted. In the center
position the high EQ has no effect on the signal.
If all three EQ controls are set to kill, then the channel
is effectively muted.
22. MID EQ
This knob gives you up to 10 dB of boost at 1 kHz. In
the kill position, the mid frequency range around 1 kHz
is muted. At the center position, the mid EQ has no ef-
fect on the signal.
23. LOW EQ
This knob gives you up to 10 dB of boost at 300 Hz
and below. In the kill position, the low frequency range
below 300 Hz is muted. At the center position, the low
EQ has no effect on the signal.
GAIN
U
HIGH
EQ
+10
KILL
U
U
U
+10
KILL
MID
U
+10
KILL
U
+10
KILL
LOW
U
+10
KILL
U
U
U
+10
KILL
+14
-14
+14
-14
MID
MID
FREQ
HIGH
12kHz
LOW
80Hz
EQ
AUX
AUX
+50
+3
O
O
+15
-15
U
MAX
O
O
MAX
8k
100
600
+15
-15
U
+15
-15
U
+15
-15
U
+15
-15
U
+15
-15
U
+25
-22
MIC
+50
+3
+25
-22
MIC
150
1.5k
8k
100
600
150
1.5k
CURVE
GAIN
1
2
3
4
3
4
O
O
-20
-10
+10
-5
0
5
O
O
MAX
O
O
MAX
LEVEL
O
O
MAX
O
O
MAX
LEVEL
SET
LEVEL
SET
SLOW
FAST
OL
10
7
4
0
4
10
20
POWER
48V
L
R
MAX
FW IN
MAX
O
O
O
O
MAX
PHONES
O
O
CUE
LOOP
OUT
CUE
CUE
CUE
CUE
48V