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,

20Hz–20 kHz.) Channel input to any output, below

.0025% typical. Attenuation (1 kHz @

0dBu. 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

100kHz, +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 kΩ. All other in- puts, 10 kΩ. All outputs, 120 kΩ.

Equalization. Lo EQ Shelving @ 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.

LM-3204E Expander

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

1through 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.

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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

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