Specifications

ManualsBrandsShure ManualsAmplifierSR10

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

DATA

MODEL SR108 EXTENDED

AREA CODE312/866-2200 CABLE: SHUREMICRO

SHEET

RANGE SPEAKER SYSTEM

TWX: 910-231-0048 TELEX: 72.4381

OPERATION AND SERVICE INSTRUCTIONS

FIGURE

SR108 SPEAKER SYSTEM

DESCRIPTION

The Shure Model SR108 Extended Range Speaker

System is a rugged, heavy-duty, two-way speaker sys-

tem designed primarily for high sound-pressure-level

reproduction of wide-frequency-range program mate-

rial in sound reinforcement applications. The

SR108

can be used with Shure Model SR105 or similar high-

power amplifiers, in either a single-amplifier mode

(conventional full-range operation with passive cross-

over) or, with a Shure Model

SR106 Electronic Cross-

over, in a biamplification mode of operation. The

SR108

is also ideal for monitoring applications requiring wide

frequency response and high signal level capabilities.

When properly installed and connected, the

SR108 will

provide outstanding performance in critical, high-level

applications due to its extremely wide frequency re-

sponse, low distortion and smooth dispersion charac-

teristics. The

SR108 has a nominal impedance of 16

ohms and is designed to operate with up to 57 volts

rms input (200 watts continuous program material). In

the biamplification mode, the low-frequency section

accepts up to 200 watts and the high-frequency section

up to 100 watts of continuous program material. The

SR108 can be used either direct-coupled or with a

constant-voltage 70-volt line using a Shure

A102A

Transformer.

The superior sound quality of the

SR108 is achieved

through the use of six eight-inch low-frequency speak-

ers, mounted in a linear array in a front-ported,

horn-

loaded, bass reflex enclosure (fourth-order Butterworth

response) plus four high-frequency drivers coupled

to a single radial horn. The front-porting bass reflex

design of the enclosure provides extreme

low-fre-

quency enhancement, and horn-loading optimizes the

lower mid-range frequencies. A built-in series-type

passive crossover network is used with single-amplifier

inputs, and includes a four-position high-frequency

attenuator switch (LOUDSPEAKER OPERATION).

The LOUDSPEAKER OPERATION Switch is also

used to select between the single-amplifier, passive

crossover input and separate high- and low-frequency

inputs for operation in the biamplification mode. The

Shure Model

SR106 Electronic Crossover provides

the proper low-frequency and high-frequency signal

splitting ahead of the power amplifiers for biamplified

operation.

The high-frequency section of the

SR108 also con-

tains automatic protection circuitry to avoid driver

damage at extremely high input levels. Additional

high-frequency driver protection is included in the

bi-

amplification mode to protect against damage from

low-frequency signals.

The

SR108 is a portable unit, and is primarily de-

signed for easy installation either indoors or in

a protected outdoor environment, such as under an

open pavilion. The system is supplied with a

15.2111

(50-foot), 18-gauge, rubber-jacketed connecting cable

with phone plugs. (A second connecting cable-Shure

No.

RKC4, not supplied-is required for operation in

the biamplification mode.) The upper right rear section

of the

SR108 contains a cable storage compartment.

The

SR108 is constructed of 15.9 mm

(5/8

in.) heavy

durable wood, coated with black, scuff-resistant, tex-

tured vinyl. All adhesives used in the

SR108 are

moisture-resistant, and internal bracing is provided to

minimize vibration and maximize structural integrity.

The metal grille assembly is finished in durable gold

enamel. The radial horn is ruggedly constructed of

high-density, structural urethane foam, with fastening

hardware selected to provide strength and minimize

corrosion and visible wear. The

SR108 is equipped

with an integral rear-panel handle and two heavy-duty,

hard-rubber wheels for mobility.

1977,

Shure Brothers

Inc.

27A1355

(QC)

Printed

U.S.A.

Summary of content (16 pages)

PAGE 1
222 HARTREY AVE., EVANSTON. IL. 60204 U.S.A. @ AREA CODE312/866-2200 TWX: 910-231-0048 CABLE: SHUREMICRO TELEX: 72.4381 I DATA SHEET 1 MODEL SR108 EXTENDED RANGE SPEAKER SYSTEM OPERATION AND SERVICE INSTRUCTIONS the biamplification mode, the low-frequency section accepts up to 200 watts and the high-frequency section up to 100 watts of continuous program material. The SR108 can be used either direct-coupled or with a constant-voltage 70-volt line using a Shure A102A Transformer.
PAGE 2
SPECIFICATIONS Power Rating (Program Material) Single Amplifier lnput..200 watts max. Low-Frequency lnput (Biamplification Mode)..200 watts max. High-Frequency lnput (Biamplification Mode)..100 watts max. Power Load for Constant-Voltage Operation .................... 39 watts (25-volt input, 16 ohms) 50 watts (70.7-volt input, through optional A102A Transformer) Impedance ....................3 6 ohms nominal for both conventional full-range and biamplified operation (see Figure B) Frequency Response ....
PAGE 3
r"":: r.~? CONENTICUM FULL-RANGE lpUr n PASSIVE HIGH-FI1EWENCY ATTENUATION m g m E R (4- 3/8IN.) I FULL RANGE 1 FULL-RANGE BUW LOI-FREOUENCI WUT O\ 1 1 w -0 8 m C n SHOWN N FULL RAW€ W K N FIGURE F. SR108 BLOCK DIAGRAM high-frequency drivers which are wired in seriesparallel and provide a total nominal impedance of 16 ohms. FIGURE E.
PAGE 4
covering a wide area, each SR108 should be positioned so that its angle of coverage slightly overlaps that of the SR108 next to it as their sound output enters the audience area. The problem of audience penetration may be likened to illuminating a dark area with a floodlight: the object is to provide maximum area coverage (audience) with the available floodlights (SR108's). At the same time, care must be taken to avoid illuminating reflective surfaces.
PAGE 5
used as long as all low-frequency sections are in phase with one another and all high-frequency sections are in phase with one another. A potential problem exists only when there is a phase reversal between the high- or low-frequency sections of the speaker systems in use. To check for a possible out-of-phase condition, the following listening test should be performed on both high- and low-frequency sections of the SR108's.
PAGE 6
FIGURE L. RECOMMENDED WIRE GAUGE: 70-VOLT AMPLIFIER OUTPUT (USING A102A TRANSFORMER) audience, curtains or stage sets may cause inadvertent movement (tipping or sliding). If potentially hazardous locations cannot be avoided, the SR108's should be secured with rope, cable or strapping to maintain their physical positions and prevent accidents.
PAGE 7
Circuit Description Biamplified operation is accomplished by feeding separate high- and low-frequency signals from an external 2600 Hz active crossover network, such as the Shure Model SR106 Electronic Crossover, through separate high- and low-f requency power amplifiers, such as the Shure Model SR105 Power Amplifier, to the HlGH and LOW FREQ lnput Jacks of the SR108 (see Figure G).
PAGE 8
apply. As in conventional full-range operation, the second HIGH and LOW FREQ lnput Jacks may be used for additional, parallel-connected biamplified SR108's. BASIC OPERATING HINTS Should any difficulty be encountered in SR108 operation, the problem may often be traced to some simple source such as an er.ror in interconnection. The following is offered as a basic guide to problems of this sort. Symptom: SR108 is "dead" (no output) Check: 1. Check inputs and outputs of all equipment driving SR108. 2.
PAGE 9
PAGE 10
Sound from low-frequency speakers should be clean and free from buzzes or rattles which may indicate speaker failure. Replace any speakers found defective. Be sure to resolder disconnected leads and fasten all hardware securely to avoid rattles. High-Frequency Driver Replacement To replace a high-frequency driver, follow these steps: 1. Disassemble the high-frequency driver assembly as described in Speaker Servicing. 2. Unsolder leads from driver terminals. 3. Remove three 6-32 x 1% in.
PAGE 11
2. Remove upper rear panel as described in Speaker Servicing above. 3. Unsolder high-frequency driver assembly leads (black and green) from inductor assembly L2, and place a dummy load (16 ohms, 50 watts minimum) across L2. 4. Connect an ac voltmeter (Simpson 260 or equivalent) across dummy load. 5. Apply a 5 kHz ac voltage from a power amplifier across one HlGH FREQ/BIAMP OPERATION Input Jack (J5 or J6). Slowly increase voltage until 28 Vac is reached.
PAGE 12
\SPEAKER CABINET I CROSSOVER ASSEMBLY SWITCH S1 el - INDUCTOR ASSEMBLY L2 FIGURE P. Table 1. Item 12 Qty. Shure Part No.
PAGE 13
REPLACEMENT PARTS LIST (See Figures Q and R) Reference Designation Replacement Kit Consists Of: Replacement Kit No.* Q~Y. Part No. Description - 90A2063 Crossover Network Assembly A2 - 90A2068 High-Frequency Driver Assembly (LS7-LS10, A3) A3 - - 90A2064 High-Frequency Driver Throat Assembly (without drivers) A4 - - 90E1375 Jack Panel Assembly (including connectors) 1 94A1182 High-Frequen~yDriver Diaphragm and Coil Assembly - 50A71 Capacitor, Metallized Mylar, Non-polarized, 4.
PAGE 14
REPLACEMENT PARTS LIST (Continued) Reference Designation Replacement Kit Consists Of: Replacement Kit No.* Qty. - - MP15 - - MP16 - MP17 Part No. Description 95A638 Wheel 95A641 Cable Compartment Strap and Socket Assembly 48A47A Rail 36A336 Foam Screen 30C806C Phillips Finishing Head ThreadCutting Screw, Black, #8, 1 in. (Horn, Upper and Lower Rear Panels to Enclosure) - 30D832D Phillips Flat Head Wood Screw, #6, % in.
PAGE 15
FIGURE Q.
PAGE 16
ARCHITECTS' AND ENGINEERS' SPECIFICATIONS The Speaker System shall be an extended range, two-way speaker system designed for high sound-pressure-level reproduction of wide frequency range program material in sound reinforcement applications. The Speaker System shall utilize six 8-inch cone-type speakers with a total speaker cone area of 1097 cm2 (170 in2) and four high-frequency drivers. Pressure sensitivity of the Speaker System shall be an EIA rating of 54 dB at 9.