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Model 577B User Guide
27C1128 (Rev. 5) Printed in U.S.A.
©2013 Shure Incorporated
TABLE 1. CABLE-TO-CONNECTOR WIRING
INPUT TYPE WIRE
COLOR
FUNCTION XLR
CONNECTOR
1/4 IN.
PHONE
PLUG
BALANCED
WHITE AUDIO+ PIN 2 TIP
GREEN AUDIO – PIN 3 RING
SHIELD CHASSIS
GROUND
PIN 1 SLEEVE
UNBALANCED
WHITE AUDIO -- TIP
GREEN AUDIO
GROUND
-- SLEEVE
SHIELD CHASSIS
GROUND
-- SLEEVE
NOISE-CANCELING HANDHELD DYNAMIC MICROPHONE
GENERAL
The Shure Model 577B SONOBAR
®
Microphone is a handheld dynamic
microphone designed for communications and paging applications that
require highly intelligible, low noise output. It can be used in all types of
mobile communications, from amateur radio to helicopter news and traffic
reports. It is also suitable for public address and paging systems in noisy
areas such as factories, airport terminals, and restaurants.
The 577B represents a significant improvement over most microphones
with anti-noise features. Shaped frequency response, directionality,
and distant sound discrimination contribute to total noise reduction. The
microphone operates on the pressure-gradient principle and has two sound
entry ports spaced a small distance apart.
The modular design of the 577B greatly facilitates field servicing. The
cartridge, switch, and cable can be replaced in a matter of minutes, if
necessary.
The 577B is built to withstand mechanical shocks, vibration, high
temperatures, and humidity. The exclusive ARMO-DUR
®
case is impervious
to oil, grease, fumes, salt spray, sun, and corrosion. he “Million-Cycle”
press-to-talk switch ensures years of reliable service.
A mounting bracket is supplied to provide convenient hang-up when the
microphone is not in use.
Features
• Frequency response tailored for close-talk operation
• Extremely effective noise cancellation
• Dynamic microphone cartridge
• Modular design
• “Million-cycle” leaf-type press-to-talk switch
• TRIPLE-FLEX
®
cable provides three to four times the flex life of
most coiled cords
• Rugged ARMO-DUR
®
case
• Built-in hang-up button and supplied mounting bracket
OPERATION
For optimum performance and maximum rejection of background noise,
place your upper lip against the lip guard, approximately 25 mm (1 in.)
from the grille. Hold down the push-to-talk button while talking normally.
INTERNAL CONNECTIONS
The 577B is a balanced-line, low-impedance dynamic microphone. It is
designed for direct connection to low-impedance microphone inputs and/
or installations where long cable lengths are needed. It includes a four-
conductor (two conductors shielded) coiled-cord cable and a double-pole,
single-throw, leaf-type switch. The WHITE and GREEN leads are the “hot”
audio conductors; the shield is connected to microphone circuit ground. The
RED and BLACK leads control the switch circuit. The microphone circuit
is open when the switch is open, but can be easily modified for normally
shorted operation. Refer to Figure 1.
WHITE
INTERNAL CONNECTIONS
FIGURE 1