MACKIE LM-3204 - Manual (Page 9)

9
EQ
In keeping with the stereo theme of this entire
mixer, the engineers at Mackie have decided to
provide stereo equalization as well. Just like the
stereo Gain control, the EQ knobs have both left
and right EQ sections ganged on a single shaft.
The LM-3204 EQ has three sections, each
with a fixed knee or center frequency and
bandwidth. Frequency curves are shown below.
The low-frequency equalizer is a shelv-
ing EQ with the knee of the shelf set at 80 Hz.
The Lo section offers a swing of
±
15dB.
The mid-frequency EQ is a peaking EQ,
featuring a bell-shaped peak/dip curve cen-
tered at 2.5 kHz with a smooth-sounding
2-octave bandwidth. The Mid section can cut
or boost over a range of
±
12dB.
The high-frequency equalizer is a shelv-
ing EQ with the knee of the shelf set at 12
kHz. Like the Lo section, the Hi section offers
a swing of
±
15dB at a very useful frequency.
When any of the EQ knobs are set at their
“Unity” detents, that section is effectively out
of the circuit.
AUX SENDS
The LM-3204 offers 4 separate sets of auxil-
iary sends from each input module. Two sets
of sends per module can be selected at any
one time. The Shift switch
allows you to
choose either sends 1 and 2, or sends 3 and 4
on any channel strip.
Sends 1 and 3 , selected alternately by
the Shift button, are true stereo sends with
left and right channels maintained separately
throughout the auxiliary send circuitry.
Sends 2 and 4 , also selected alternately
by the Shift switch, are mono sends. Within
each channel strip, the left and right input
signals are combined into a mono sum for
sends 2 and 4, which appear at their output
jacks as monaural signals.
All the sends on the LM-3204 are post-Gain
control, post-EQ, post-Mute switch. Unfortu-
nately, due to the incredibly dense surface
mount circuitry inside this beast, modifica-
tions are not possible.
Each AUX send control has a “Unity” de-
tent at the top of its travel, and, like the rest
of the mixer, will deliver a “level in = level
out” signal at the send outputs when set to
“U.” Setting the aux send controls fully clock-
wise delivers a whopping +15dB of gain.
THE MASTER OUTPUT SECTION —
THE TOUR CONTINUES
The Master Output section is that right-hand
one-fifth of the LM-3204 we promised we’d talk
about earlier in the manual. This section is
home to the Master Faders, Control Room,
Headphone and Solo level controls, the AUX Re-
turns and, of course, the Rude Solo Light.
LEFT AND RIGHT MASTER FADERS
The mix level of the main Left and Right
buses is controlled by the Left and Right
Master Faders. The unity gain point for the
mix output circuits is marked with a “U,”
with 10dB of gain available beyond that
point. When both channel strip Gain and
the Left and Right Master Faders are set at
unity, the output level of the LM-3204 will
be the same as the input level.
LEFT AND RIGHT METERS
Above the Master Faders are the Left
and Right Meters. These are peak averag-
ing meters, with zero (0)dB referenced to
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
LM-3204 Lo shelving EQ
±
15dB boost/cut.
LM-3204 Mid peaking EQ
±
12dB boost/cut.
LM-3204 Hi shelving EQ
±
15dB boost/cut.
U
+30dB O O
BALANCE
L
–15 +15
U
–12 +12
U
2 +15 O O
U
–15 +15
U
1
+15 O O
U
16
SHIFT
-20
OL
4
3
12k
STEREO
MONO
HI
80
LO
2.5k
MID
EQ
SOLO
AUX
L R
16
CHANNEL
MUTE
ALT 3-4
GAIN
GAIN
10
22
+20 O O
U
1
LEVEL
+20 O O
U
2
+20 O O
U
3
LEVEL
+20 O O
U
4
STEREO AUX RETURNS
AUX RETURN
TO CONTROL
ROOM ONLY
SOURCE
ALT 3-4
40
30
20
10
7
4
2
0
2
4
7
+
–
CLIP
PHONES
O O
SOLO
+20 O O
U
TAPE
MONITOR
LEVEL
POWER LM-3204 STEREO LINE MIXER
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dB
20
15
5
10
O O
5
10
30
40
U
dB
20
15
5
10
O O
5
10
30
40
U
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LEFT RIGHT CONTROL R M