Shure Pro Master 702 User Guide

222

HARTREY

AVE.,

EVANSTON,

IL.

60204

U.S.A.

MODEL

702

STAGE MONITOR

AREA CODE 3121866.2200 . CABLE: SHUREMICRO

TWX: 910-231-0048 TELEX: 72-4381

SPEAKER SYSTEM

OPERATION AND SERVICE MANUAL

DESCRIPTION

The Shure Model 702 is a high-quality, two-way loud-

speaker system designed for localized sound coverage in

on-stage monitor (foldback) applications. The 702 may be

used with virtually any power amplifier capable of deliv-

ering up to 50 watts to a 16-ohm load. The Speaker may

be placed in either of two slanted positions facing the

performer.

Excellent sound reproduction is achieved through the

use of two

&inch heavy-duty speakers and three piezo-

electric tweeters. The tweeters are arranged in a

cross-

firing configuration, providing uniform horizontal cover-

age. A volume control permits individual adjustment of

702 volume to suit each performer's needs. Nominal

impedance of the Speaker is 16 ohms with the volume

control at 10. Reduction of the volume control setting

reduces the overall volume and increases the Speaker

impedance. At the

0 setting, the Speaker is turned off.

If the 702 is the only Speaker connected to the amplifier,

the 702 volume control should be set to

10 and the

amplifier volume control adjusted as desired.

The 702 is constructed of 15.9 mm

in.) wood and

covered in scuff-resistant black vinyl. The attractive black

sculptured fabric grille is rugged, cleanable, and replace-

able if damaged. A retractile handle and balanced design

contribute to ease of transporting. The corners of the 702

are equipped with steel protectors. Rubber feet on two

surfaces provide protection and offer the option of posi-

tioning at either a

30" or 60" angle to the stage.

A heavy-duty,

15m (50 ft), 18-gauge, rubber-jacketed

connecting cable with phone plugs is available as Shure

Model

RKC4, and a rugged vinyl slip-on protective cover

is available as Model

A702A.

SPECIFICATIONS

Power Rating

........

.Maximum recommended ampli-

fier output: 50 watts

continuous, 28 Vrms, 48V peak

to 16 ohms

Impedance

..........

.16 ohms nominal (volume

control at 10)

Frequency Response

,100 Hz

20 kHz (see Figure 1)

optimized for natural

wide-

range voice reproduction

TYPICAL FREQUENCY RESPONSE

FIGURE

Sound Pressure

........

Level (SPL) .EIA rating: 49.5 dB at 9.2m

(30 ft) from 1 milliwatt;

equivalent to 97 dB at 1.2m

(4 ft) with 1-watt input

Phasing (Polarity)

....

.Positive voltage on phone jack

tip produces positive sound

pressure

High-Frequency

...........

Section .Three piezoelectric tweeters

(cross-firing)

Low-Frequency

...........

Section .Two

in. speakers

Horizontal Distribution.

.SO0 (see Figure 2)

LEGEND

...........

kHz

TYPICAL POLAR PATTERNS

FIGURE

27A1352

(SL)

Printed in

U.S.A.

Vertical Distribution

.llOO

Directivity Factor

(Q)

. . . . . .

. . .

.8.1 at 1 kHz full octave measure-

ment

Environmental Resistance:

Operating

Temperature.

. . . .

7" to 43°C (20" to 110°F)

Storage

Temperature

. .

. . .

29" to 71 "C (-20" to 160°F)

Connectors

. . . .

.Two parallel-wired phone jacks

Overall Dimensions

.395 mm H x 533 mm W x 264 mm

(15-9/16 in. x 21 in. x

10-3/8 in.)

Weight

. .

. . .

.9.1 kg (20 Ib)

Construction

. .

.15.9 mm (5/8 in.) wood, black

vinyl covering, black fabric

grille, retractile handle, steel

corner protectors, rubber feet

Optional Accessories

RKC4 15m (50 ft) cable with

phone plugs

A702A Protective Cover

INSTALLATION

General

Position the 702 at the front of the stage in front of the

performer's microphone, with the speaker grille aimed

approximately at the back of the microphone. Note that

the 702 may be used at either a 30" or

60" angle to the

horizontal. The angle chosen should be that which pro-

vides the most direct line-of-sight to the performer and

also provides minimal visual interference with the audi-

ence. When only one 702 is used on a separate amplifier,

set the 702 volume control to 10 and adjust the amplifier

or mixer controls as desired. When several 702s are used

on the same amplifier, set at least one 702 volume con-

trol to 10 and adjust the others as necessary. Setting at

least one 702 to 10 will ensure maximum undistorted out-

put from the amplifier.

It is possible to optimize the 702 (maximum gain before

feedback, most natural sound, etc.), for various room con-

ditions with an equalizer such as the Shure Model

SR107

Audio Equalizer. Optimum system sound may be ob-

tained by "tuning" the equalizer with an equalization

analyzer system such as the Shure Model

M615AS.

Direct Amplifier Connection

The Speakers are designed to be used with power am-

plifiers having the following maximum output capabilities:

However, sine-wave signals delivering 50 watts to a

Speaker should be avoided in that they present a much

greater average power than does program material. Con-

sequently, when setting up or adjusting a sound system

with these Speakers, avoid the use of high-level,

continuous-type test signals.

Speaker Wiring

Determine the approximate distance from amplifier to

Speaker and use the proper wire gauge. Recommended

cables for the sizes listed are:

Distance

AWG

Suggested Cable

0-30m (0-100

ft)

18 Gauge Belden #8460, #8461, #9740, Sf8542

30-60m (100-200

ft)

I6 Gauge Belden #8470, #8471, #a472

To avoid the frequency losses, poor coverage, dead

zones, etc., resulting from improper speaker phasing in

multiple Speaker installations, all Speakers must be wired

in proper polarity. The cables listed above are

color-

coded to insure that identical connections are used. Note

that even common 18-gauge lamp cord ("zip cord") is

phase-coded with ribs along the outer jacket of one con-

ductor.

The Shure RKC4 is a

15m (50 ft), 18-gauge, rubber-

jacketed cable with phone plugs on both ends. The

unused phone jack may be used for additional,

parallel-

connected Speakers.

Checking Sound Coverage

When the Speakers, amplifier and other equipment

have been installed and connected, apply a fairly con-

stant level signal to the system (preferably pink noise or

program material) and walk around the stage area. Listen

for a smooth, even output from the Speakers, with mini-

mal differences in volume and tone, and no unclear or

"dead" spots. A dead spot-for audio purposes, an area

where no sound is heard, or where the sound level is

appreciably lower-may mean that the Speakers are not

covering that area, or that the speaker wires are con-

nected out-of-phase. Proper phasing may be readily

determined by checking the connections on each Speak-

er, but inadequate coverage generally requires Speaker

repositioning or adding Speakers.

SERVICE

INSTRUCTIONS

Speaker Servicing

1. Using an ohmmeter, measure the resistance be-

tween the tip and sleeve of a phone plug inserted

in a speaker jack. The dc resistance should be 12

to 16 ohms with the volume control at 10.

2. To gain access to the individual speakers, remove

the Phillips head screws on the grille.

3. Using an ohmmeter, measure the resistance of each

speaker voice coil. A clicking sound will be made

by a "good" speaker when an ohmmeter is con-

nected or disconnected. Note that the resistance

of each

&inch speaker cannot be measured with-

out disconnecting a lead from one of its terminals.

Each 8-inch speaker should measure between 7.5

and 9.5 ohms. The piezoelectric tweeters are capac-

itive and cannot be measured with an ohmmeter;

the capacitive value of each tweeter should be

between

.ll

and .I7 mF.

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