between the mixer and the
optional expander unit(s), if
used; and which shall be
designed to mate with the
connectors on the expander
ribbon cable provided with
each Expander unit.
16. PHYSICAL CONFIGU-
RATION.
The mixer shall
have a steel chassis frame
painted grey-black and
designed to mount in a
standart 19" relay rack. The
mixer’s dimensions shall be
8.73" high (5 rack units) by
19.00" wide (rack ears are
built-in) by 9.66" deep.
17. OVERALL MINIMUM
SPECIFICATIONS.
In ad-
dition to specifications
previously cited, the
mixer shall meet or
exceed the following
performance criteria:
Noise.
(20 Hz–20 kHz
bandwidth, Line inputs to
Main L/R outputs, all chan-
nels assigned.) Master
fader down, Channel gains
down, –104.2 dBu. Master
fader unity, Channel gains
down (Mix Noise), –86.6
dBu. Master fader unity,
Channels gains unity,
–84.0 dBu.
Total Harmonic Distortion.
(1 kHz @ +14 dBu,
20 Hz–20 kHz.) Channel
input to any output, below
.0025% typical.
Attenuation
(1 kHz @
0 dBu. 20 Hz–20 kHz
bandwidth, Channel in, to
Main Left outputs.) Chan-
nel gain down, –73 dBu.
Channel muted, –81 dBu.
Frequency Response.
(Any input to Main out-
put.) 20 Hz to 60 kHz,
+0 dB/–1 dB. 10 Hz to
100 kHz, +0 dB/3 dB.
Maximum Levels.
Mic
preamp input, +14 dBu. All
other inputs, +22 dBu. All
outputs, +22 dBu.
Impedances.
Mic preamp
input, 2.5 k
Ω
. All other in-
puts, 10 k
Ω
. All outputs,
120 k
Ω
.
Equalization.
Lo EQ Shelv-
ing @ 80 Hz,
±
15 dB. Mid
EQ Peak @ 2.5 kHz,
±
12 dB. Hi EQ Shelving @
12 kHz,
±
15 dB.
Microphone Preamp.
E.I.N.
(150
Ω
terminated, maxi-
mum gain), –129 dBm.
18. DESIGNATION.
The
audio mixer shall be a
Mackie Designs LM-3204.
21. INPUT CHANNEL
CONNECTIONS.
Each
expander input channel
shall have a left and a right
electronically balanced line-
level input, accommodating
a nominal line level of
between –10dBV and
+4dBu, and appearing on
the rear panel as
1
/4" TRS
phone jacks (tip hot, ring
cold). The jacks shall be
fitted with internal switches
to accommodate monaural
configuration. Additionally,
input channels 1 through 4
shall offer left and right
unbalanced insert connec-
tions, appearing on the rear
panel as
1
/4" TRS phone
jacks (tip send, ring return).
22. INPUT CHANNEL LEVEL
AND ASSIGNMENT CON-
TROLS AND INDICATORS.
Each expander input chan-
nel shall be equipped with a
rotary dual gain control, a
solo switch, a mute switch
which also functions as an
assignment switch to the
alternate output channels,
and a stereo balance
control. Additionally, any
soloed channel(s) shall have
their –20 and O/L LEDs light
steadily, to indicate a solo
condition.
23. INPUT CHANNEL
EQUALIZATION.
Each
expander input channel shall
be equipped with a stereo
equalization function. The
equalizer shall have three
sections: a low-frequency
shelving equalizer with the
knee set at 80Hz and a range
of
±
15dB; a mid-frequency
peaking equalizer centered
at 2.5kHz featuring a band-
width of 2 octaves and a
range of
±
12dB; and a high-
frequency shelving equalizer
with the knee set at 12kHz
and a range of
±
15dB.
24. INPUT CHANNEL
AUXILIARY SENDS.
Each
expander input channel
shall have one stereo
19. GENERAL
CONFIGURATION.
The
expander unit shall not be
designed to operate alone,
but in conjunction with a
Mackie Designs LM-3204
Line Mixer. The expander
shall have a rack-mount-
able frame which accom-
modates 16 stereo input
channels. Each input
channel shall be capable of
accepting either stereo or
monaural signals, and shall
be fitted with stereo level,
equalization, balance, solo,
muting and auxiliary send
controls, level-indicating
(–20) LEDs and overload
(O/L) LEDs. Input channels
1 through 4 shall each be
fitted with left and right
insert jacks.
Additionally, the expander
shall include 4 stereo
effects return inputs.
20. POWER SUPPLY.
All
necessary operating voltages
for the expander shall be
provided by an internal
shielded power supply.
3
3
LM-3204E Expander
