Emtech Electronics IA-204S User Manual
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Mount the RCM-42B in a convenient location, such as next to the power supply.
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There are 4 screw terminal connectors on the RCM-42B. Each of these connectors is labeled for a specific
room, room one through room four.
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The room one connector has two extra pins for the power supply inputs.
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The INPUT – and INPUT + terminals are connected to the SEND – and SEND + wires from the IA-204.
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The OUTPUT – and OUTPUT + terminals are connected to the RETURN – and RETURN + wires from
the IA-204.
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The cables connecting the inputs and outputs between the IA-204 and the RCM-42B must be shielded.
Terminate the shielding at the RCM-42B only! Each orange connector on the RCM-42B has two terminals
labeled GROUND for this purpose.
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The BUSS A and BUSS B pins connect directly to the IA-204R. BUSS A connects to pin 3 (labeled C) on
J5 (4 pin orange connector), and BUSS B connects to pin 4 (labeled C) on J5.
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If using the IA-204S, a separate switch must be installed for room mixing. A single-pole, double-throw
center off switch is required for switching between GROUP A and GROUP B (called BUSS A and BUSS B
on the RCM-42B). A three conductor non-shielded cable is required because a ground connection must be
made from the RCM-42B to the middle pin of this switch.
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To combine rooms, change the ROOM MIXING switch on the IA-204R from LOCAL to GROUP A or
GROUP B. Repeat this step on any other IA-204R that is to be combined. IA-204’s on the same GROUP
setting can now share program material.
BALANCING EACH IA-204
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Each IA-204 has a trimmer control on the back of the circuit board. This control is used for balancing the
sound level in individual rooms so that when movable partitions are opened and the room combining feature
is used, the sound level is balanced room to room, regardless of room size or speaker configuration.
OPTIONAL METHOD OF BALANCING ROOM SOUND FOR ROOM COMBINING
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To set this control properly, pink noise should be fed into any one of the common area IA-204’s and its
ROOM MIXING switch should be set to one of the GROUP positions. Set the ROOM switch to the same
GROUP position on the other IA-204’s that are feeding the common area. Set the volume control of the
“master” IA-204 to the 12:00 position and the trimmer control(s) should be adjusted on the “slave” IA-204’s
while monitoring the sound pressure level with a SPL meter. After the sound level has been balanced in each
room, feed the pink noise into one of the “slave” 204’s that was adjusted previously and then adjust the
trimmer control on the 204 that was the “master” before until proper balance is achieved. Now, any IA-204
can be a “master” or a “slave” in perfect balance. Refer to operation section of this manual. Verify that
power is available to the IA-204 by turning on other IA-204’s sharing the same power supply.