Handbook for Sound Engineers

Intercoms 1571

box office. The producer and director have access to all
four channels. The lighting director is limited to the
floor and light crew. The audio engineer can access the
floor crew and channel D audio. Note the majority of
the belt packs is single channel. There is no reason for
the lighting crew to talk to the dressing rooms, which
keeps conversations specific to their assigned channels.

All cabling is standard low capacitance shielded micro-

phone audio wiring.

43.2.3 Broadcast Matrix Systems

Matrix systems are a powerful and cost-effective

communications tool. Expansion is easy and installation

is inexpensive as only a single pair of wires is required

for audio, signaling, and external inputs. System size

ranges from 2 × 2 to over 784 × 784.

There are two basic methods of interconnection

between matrix intercom stations and the central frame:

analog audio and fully digital.

The two-wire party line matrix system is a very flex-

ible multi-channel party line where numerous sources,

or drops, are connected to an 8ft × 24ft assignment

panel. The drops can be mixed. The example of Fig.

43-13 reflects twenty four drops across eight PL chan-

nels. The configuration permits the user to program any

one of the twenty four locations to a specific PL

channel. For example, one day you might need a camera

position at stage left and tomorrow the lighting crew

might use that location. You may also route wireless

intercom, two-way radios, and fiber remote links to any

Figure 43-10. Two-channel party line system. Courtesy Clear-Com Communication Systems.

MENS DRESSING

ROOM

WALLMOUNTEDSTATION

LADIES

DRESSING ROOM

F 3-PIN

YC-36

M 6-PIN

DUALCHANNEL

BELTPACK

6-PINXLR

WALLMOUNTEDSTATION

SINGLECHANNEL

BELTPACK

SINGLECHANNEL

BELTPACK

AUDIO

FLASHER

STAGEMANAGER STAGEHAND

CHANNEL-A CHANNEL-B

STAGE ANNOUNCEOUT TO PA SYSTEM PROGRAM IN

CC-95

DIRECTOR

FO BACK

STAGE

STAGE RIGHT STAGE LEFT

CATWALKRIGHT

CHANNEL-A

CHANNEL-B

CHANNEL-A

CATWALKLEFT

CHANNEL-B

CHANNEL-A

TWO CHANNELWIRELESS

TWO CHANNEL MAIN STATION

Figure 43-11. A party line belt pack. Courtesy Clear-Com

Communication Systems.