Handbook for Sound Engineers

1576 Chapter 43

Attention must be paid to acoustical and electrical
isolation between the microphone and earphone(s) to
minimize the common problem of crosstalk in multiple
channel intercom systems. Also by using dual chamber
foam filled ear cushions, the acoustical isolation of
earphones allows for comfort and low ear fatigue in
high-noise environments.
Broadcast-quality microphones require noise
rejecting abilities with wide-frequency response and
good resistance to breath and wind noise as the micro-
phone is usually very close to the lips. Boom micro-
phones can be adjusted to any position, and located as a

right or left hand headset with positive detent stops. In

addition, the boom can be bent into any required posi-

tion. Often swinging the boom up shuts off the micro-

phone to eliminate feedback and unwanted noise.

The headset cable is specially designed to minimize

crosstalk between the microphone and the earphone.

The wire stranding is a special composition for flexi-

bility and resistance to breakage.

Earphones have specially contoured wide-band-

width frequency response and a sensitivity of

94 dB SPL with 1 mW of power. This reduces ampli-

fier power, increasing battery life.

Figure 43-16. Theater intercom system. Courtesy Clear-Com Communication Systems.

Curtain operator headset

Stage

pickup mic Patch panel headset

Light board headset

Dressing rooms

Green room

Stage manager

Wall-mounted intercom stations

Program

input

(B) Ch

(A) Ch

(A) Ch

Spot light operator headsets