Shure 548SD User Guide

222 HARTREY AVE.. EVANSTON. IL. 60204 U.S.A.

8

8

AREA

CODE

AREA CODE 3121866-2200 CABLE: SHUREMICRO
TWX: 910-231-0048 TELEX:

UNIDIRECTIONAL DYNAMIC MICROPHONES

3121866.2200 CABLE: SHUREMICRO
72-4381

UAIA

1

:K~T

SHEET

I

MODELS 548,548SD,

and

,

and

UNIDYNEm IV

UNIDYNE~

SERIES

SERIES

IV

548SH

548SH

I

I

GENERAL

The UNIDYNEB IV Models 548,548SD, and 548SH are
dual-impedance unidirectional dynamic microphones
shipped connected for low-impedance operation. The
units provide wide range reproduction of music and
voice and can be effectively used outdoors and indoors.

The UNIDYNE

entertainers in high quality theater-stage sound sys-

tems and recording, as well as in critical public-address
systems such as those used in political conventions

and legislatures, convention halls, hotels, public audi-

toriums, stadiums, cathedrals and churches.

The UNIDYNE

directional pickup pattern that provides an effective . Built-in long-life On-Off switch (548SH, 548SD, and

solution to feedback problems in reverberant locations,
permits best utilization of space in small studios,
facilitates orchestral placement,
wanted background noise. the microphone

The UNIDYNE
metal case and a shock-mounted cartridge, insensitive
to handling noise or mechanical vibration.

Models 548 and
microphones or they can be stand-mounted with the
supplied A25B slip-in swivel adapter. Model 548 is
designed for applications -where a switch is not re­quired; Model 548SD is equipped with a magnetic reed

On-Off switch. Model

the attached swivel assembly for stand-mounting.

Model 548SD-CN: Same as Model 548SD, except
supplied with professional three-pin male audio con- fessional audio-connector on equipment end of
nector on equipment end of cable. (See Specifications cable (548SD-CN), and with On-Off switch mounted
for details on cable.)

IV is ideal for use by professional

IV has an exceptionally uniform uni-

and excludes un-

IV features an extremely rugged all

548SD can be used as hand-held

548SH has an On-Off switch on

VARIATION Available in four versions: without switch (548),

Microphone Features:

.

Unusually effective cardioid (unidirectional) pickup
pattern reduces feedback (annoying loudspeaker

"squeals") and prevents echoing (boominess) that
sometimes occurs in partially filled halls. Can also
be used closer to loudspeakers than usual without
creating feedback problems

Response especially effective for announcing, nar­ration, vocal and instrumental music

Shock-mounted cartridge for quiet operation
Convenient selection of either high or low imped-

ance

548SD-CN)

.

Rugged professi~nal three-pin audio connector on

.

Strong, detachable cable especially selected for
effective shielding from hum pickup

.

Supplied with an .050" wrench and a 4-40 socket
setscrew (see Figure 4) to securely lock the micro­phone to the cable connector (548,
548SD-CN)

.

Versatile-for use in the hand or on a stand­indoors or outdoors

.

Rugged and dependable under all operating con­ditions

with magnetic reed On-Off
magnetic reed On-Off switch and three-pin pro-

on attached swivel assembly (548SH).

switch

548SD, and

(548SD), with

Copyright 1980, Shure Brothers

27A1559

(TC)

Inc.

U.S. Patents

3,132,713,

Printed in

and

3,240,883

U.S.A.

SPECIFICATIONS

TY pe

Dynamic

Frequency Response

40 to 15,000 Hz (see Figure 1)

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TYPICAL

Polar Pattern

Cardioid (unidirectional)-uniform with frequency,
symmetrical about axis (see Figure 2)

Impedance

Dual. Microphone rating impedance is 150 ohms
(240 ohms actual) for connection to microphone
inputs rated at 19 to 300 ohms and "High" for con­nection to high-impedance microphone inputs. Wired
for low impedance as shipped.

Output Level (at 1,000 Hz)

Open Circuit Voltage*
Power Level**

*O dB = 1 volt per microbar

**0 dB = 1 milliwatt per 10 microbars

Switch

548SD and 548SD-CN: Built-in magnetic reed On­Off switch with lockplate. To lock switch in On
position, remove screw on lockplate and turn

plate 180". Reassemble and tighten screw.

548SH: Built-in slide-to-talk, positive detent On-Off
switch mounted on attached swivel assembly; sup-

plied with accessory lockplate.

Cartridge Shock Mount

Internal rubber vibration-isolator

Swivel

548SH: Positive action, permits tilting microphone
through

135", suitable for mounting on stand with

Ti"-27 thread

Swivel Adapter

548, 548SD, and 548SD-CN: Positive action, adjust­able through
easy removal for hand-held use, suitable for mount­ing on stand with %"-27 thread

Case

Black and satin-chrome finished all-metal case and

grille with stainless steel screen

Cable

548, 548SD, 548SH-4.6m (15 ft) two-conductor
shielded (rubber-jacketed) with a professional
pin female audio connectort on the microphone end

548SD-CN-6.lm (20 ft) two-conductor shielded
(rubber-jacketed) with a professional three-pin fe-

FREQUENCY

FIGURE

POLAR

FIGURE

RESPONSE

1

PATTERN

2

IMPEDANCE

Low

-

. . . . . -76.0 dB

High

-

-54.0 dB

(.I58 mV) (2.0 mV)

.

. . . . . . . . . .

.

-56.0 dB

90" from vertical to horizontal, permits

three-

lock-

male audio connectort on the microphone end and
a professional three-pin male audio

connectort on

the equipment end

t

Designed

A3

(Q.G.)

to

mate

series

with

or

equivalent

Cannon

XL

series,

connector.

Switchcraft

Dimensions

See Figure

3

MODELS

OVERALL

(L5f16 IN.) 41 1

MODEL

548SH

548,

548SD

AND

(1-116 IN

5fV-27

(I-Sf8 IN

3

548SD-CN

I

THD

mm

I

DIMENSIONS

DIMENSIONS

I,

-

OVERALL

FIGURE

Weight

Net

Combined

(less cable) Net Packaged

548SH 4609 7339 9449

&

548SD 31 1 g

548

548SD-CN 31 1

(16 oz)
(1 1 02)

g 7789 9759

(28% oz) (37 oz)

7239 8429

(25% 02) (33 oz)

(1 1 02) (30% oz) (38% oz)

OPERATION

Models 548, 548SD, 548SD-CN, and 548SH are dual­impedance microphones for connection to a 19 to 300
ohm rated input or to a high-impedance input. The mi­crophones are shipped from the factory connected for
low-impedance operation.

The low-impedance connection (as shipped) is
recommended where long cable lengths are required
or under conditions of severe hum disturbance. The
permissible cable length is practically unlimited since
neither response nor level is appreciably affected by
long cables. Shure Model A95 Series Line Matching
Transformers are available for use when a

low-imped­ance microphone line is desirable but the associated
amplifier has a high-impedance input. These trans­formers provide a proper impedance match between a
19 to 300 ohm microphone line and a high-impedance
input and are available with various input and output
connectors.

IMPEDANCE SELECTION

Models 548, 548SD, and 548SD-CN are shipped con­nected for low-impedance operation. To change to
high impedance (see Figures 4 and 5), proceed as
follows:

1. Remove plug element at receptacle end of mi­crophone by turning slotted setscrew in (counter­clockwise) and carefully withdrawing plug ele­ment from case.

2. Disconnect 2-terminal impedance selection sock­et from rear of plug element.