Shure 577B User Manual

NOISE-CANCELING HANDHELD DYNAMIC MICROPHONE

GENERAL

The Shure Model 577B SONOBAR
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.
The “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

®

Microphone is a handheld

Model 577B User Guide

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
NATURAL 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.

INTERNAL CONNECTIONS

FIGURE 1

TABLE 1. CABLE-TO-CONNECTOR WIRING

INPUT TYPE WIRE

COLOR

NATURAL AUDIO + PIN 2 TIP

BALANCED GREEN AUDIO – PIN 3 RING

SHIELD CHASSIS

NATURAL AUDIO -- TIP

UNBALANCED GREEN AUDIO

SHIELD CHASSIS

FUNCTION XLR

CONNECT

OR

GROUND

GROUND

GROUND

PIN 1 SLEEVE

-- SLEEVE

-- SLEEVE

1/4 INCH

PHONE

PLUG

©2005, Shure Incorporated

27C1128 (Rev. 4)

Printed in U.S.A.

CIRCUIT MODIFICATION

To modify the microphone circuit for normally shorted operation,
proceed as follows:

1. Remove the three No. 6 Phillips screws from the back of the
microphone case.

2. Separate the front and back sections of the case, and remove
the press-to-talk switch button.

3. Unsolder or clip the GREEN cable lead from the press-to-talk
switch solder lug.

4. Solder the GREEN cable lead to the GREEN cartridge lead on
the press-to-talk switch solder lug.

5. Replace the press-to-talk switch button in the front section of
the case, then join the case halves together and install the No.
6 Phillips screws removed in Step 1 above.

SPECIFICATIONS
Type

Dynamic, noise-canceling

Frequency Response

100 to 5,000 Hz (see Figure 2)

+10

Bd

0

–10

20 200001000 1000050 100

98765432

98765432

Hz

TYPICAL FREQUENCY RESPONSE

FIGURE 2

Impedance (at 1000 Hz)

Rated at 150 Ω (175 Ω actual) for connection to microphone
inputs rated at 19 to 300 Ω.

Output Level (at 1,000 Hz, 5/16 in.)

Open Circuit Voltage-66.0 dBV/Pa (0.5 mV)

0 dB = 1 volt per 1 Pascal/94 dB SPL

Hum Sensitivity

Equivalent to 32 dB SPL in 1 millioersted field

Operating Temperature Range

-40° to 74° C (-40° to 165° F)

Switch Type

Double-pole, single-throw, leaf-type, push-to-talk

Cable

Non-detachable. 1.8 m (6 ft), neoprene-jacketed coil cord,
four-conductor (two conductors shielded).

Case

Two-tone gray, high-impact ARMO-DUR

®

Dimensions

See Figure 3

45 mm

(1-25/32 IN.)

18 mm

(23/32 IN.)

MOUNTING HOLES,
CLEARANCE FOR
No. 8 SCREWS

34.5 mm

(1-23/64 IN.)

19 mm

(3/4 IN.)

4.8 mm

(3/16 IN.)

10.3 mm

(13/32 IN.)

67 mm

(2-5/8 IN.)

9.1 mm

(23/64 IN.)

9.5 mm
(3/8 IN.)

(9/16 IN.)

8 mm

(5/16 IN.)

94 mm

(3-11/16 IN.)

MICROPHONE

46 mm

(1-13/16 IN.)

36.5 mm

(1-7/16 IN.)

4.7 mm

(3/16 IN.)

MOUNTING BRACKET

14 mm

41 mm

(1-19/32 IN.)

OVERALL DIMENSIONS

FIGURE 3

Net Weight

330 grams (11.6 oz)

CERTIFICATION

Eligible to bear CE Marking. Conforms to European EMC Directive
89/336/EEC. Meets applicable tests and performance criteria in
European Standard EN55103 (1996) parts 1 and 2, for residential
(E1) and light industrial (E2) environments.

SUPPLIED ACCESSORY

Mounting Bracket (3 per kit) .......................................... RK6MB

REPLACEMENT PARTS

Cartridge ........................................................................... R98B

Cable .................................................................................. C117

Switch............................................................................RK338S

SERVICE INFORMATION

For additional service or parts information, please contact Shure's
Service department at 1-800-516-2525. Outside the United States,
please contact your authorized Shure Service Center.

SHURE Incorporated http://www.shure.com
United States, Canada, Latin America, Caribbean:
5800 W. Touhy Avenue, Niles, IL 60714-4608, U.S.A.
Phone: [phone] U.S. Fax: [phone] Intl Fax: [phone]
Europe, Middle East, Africa:
Shure Europe GmbH, Phone: [phone] Fax: [phone]

2

Asia, Pacific:
Shure Asia Limited, Phone: [phone] Fax: [phone]