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The Bi-Radial horns require the model 2506 

mounting bracket for proper installation. Proper 

mounting is shown at bracket for proper installa-

tion. Proper mounting is shown at D. The bottom 

of the mouth of the Bi-Radial horn should be flush 

with the front of the LF enclosure, and the mount-

ing bracket should be securely screwed to the top 

of the enclosure. 

Figure 12 shows how networks are mounted. 

The smaller networks, models 311 OA and 3115A, 

are mounted in cut-outs in the rear of the LF 

enclosures, as shown at A. The high-power 3152A 

is screwed onto the back of the enclosure, as 

shown at B. 

4671 

4673 

4670A 

4672A 

4674A 

PMAX = 

150 W 

PMAX = 

150 W 

PMAX = 

300 W 

PMAX = 

150 W 

PMAX = 

150 W 

SENSITIVITY: 

97 dB, 

1 W, 1 M 

SENSITIVITY: 

97 dB, 

1 W, 1 M 

SENSITIVITY: 

100 dB, 
1 W, 1 M, 

SENSITIVITY: 

103 dB, 
1 W, 1 M 

SENSITIVITY: 

103 dB 
1 W, 1 M 

EFFICIENCY: 

3.5% 

EFFICIENCY: 

3.5% 

EFFICIENCY: 

7% 

EFFICIENCY: 

6.4% 

EFFICIENCY: 

6.4% 

FIGURE 1. JBL SYSTEMS FOR SMALLER THEATERS 

TABLE I. SYSTEMS  A N D POWER 

RECOMMENDATIONS 
FOR SMALLER HOUSES 

SEATS 

VOLUME 

(APPROX.) 

SYSTEMS 

POWER REQUIRED 

FOR 100 dB 

RECOMMENDED 

AMPLIFIER POWER 

200 

1700

 M3 

(60,000

 FT3) 

4671 
4673 
4672A 
4674A 

46 WATTS 
46 WATTS 
23 WATTS 
23 WATTS 

100 WATTS 
100 WATTS 

50 WATTS 
50 WATTS 

350 

2832

 M3 

(100,000 
FT3) 

4670A 
4672A 
4674A 

30 WATTS 
30 WATTS 
30 WATTS 

50 WATTS 
50 WATTS 
50 WATTS 

500 

4530

 M3 

(160,000 

FT3) 

4670A 
4674A 

50 WATTS 
50 WATTS 

100 WATTS 
100 WATTS 

ABSORPTIVE 
MATERIAL 

2/3 

V3 

SCREEN 

FIGURE 2.  SCREEN 

MOUNTING OF 
LOUDSPEAKER 

Summary of Contents for Motion Picture Loudspeaker Systems

Page 1: ...uses usually found only in larger cities will have special effects low frequency channels such as Sensurround for special screenings of important films Motion Picture Loudspeaker Systems 2 General Acoustical Characteristics Historically motion picture theaters whatever their size have been acoustically dead rooms that is they have consider able absorption on the boundaries and rever beration times...

Page 2: ...an 0 5 dB Table II shows line losses for various runs and gauges The theater dealer should always try to speci fy a stereo amplifier which can be bridged for mono operation Care must be taken that the amplifier s bridged mono rating into 8 ohms will not be exceeded C Systems for Larger Houses 1 Choosing the system Figure 3 shows the JBL systems normally specified for multi channel use in theaters ...

Page 3: ...or using one of the many standard tilted front enclosures As a rule these are too small in volume for proper low frequency response and the client should understand this at the outset The 4671 theater system is recommended for high power surround use With an efficiency of 3 5 relatively few of these units are required They would normally be specified when the entire theater reproduction system was...

Page 4: ...ks provide for a high frequency boost which effectively makes any of the systems power flat at high frequencies In the smaller systems this may be accompanied by a slight on axis rise at high frequencies Nevertheless we recommend that the high frequency boost be used in all theater applica tions H System Assembly 2 Details of assembly We present in Figure 9 detailed wiring dia grams of each of the...

Page 5: ...74A PMAX 150 W PMAX 150 W PMAX 300 W PMAX 150 W PMAX 150 W SENSITIVITY 97 dB 1 W 1 M SENSITIVITY 97 dB 1 W 1 M SENSITIVITY 100 dB 1 W 1 M SENSITIVITY 103 dB 1 W 1 M SENSITIVITY 103 dB 1 W 1 M EFFICIENCY 3 5 EFFICIENCY 3 5 EFFICIENCY 7 EFFICIENCY 6 4 EFFICIENCY 6 4 FIGURE 1 JBL SYSTEMS FOR SMALLER THEATERS TABLE I SYSTEMS AND POWER RECOMMENDATIONS FOR SMALLER HOUSES SEATS VOLUME APPROX SYSTEMS POWE...

Page 6: ... 30 48 750 FOR 8 H LOAD LINE RESISTANCE SHOULD BE 0 552 OR LESS TABLE III SYSTEMS AND POWER REQUIREMENTS FOR LARGER HOUSES SEATS VOLUME APPROX SYSTEMS POWER REQUIRED FOR 100 dB RECOMMENDED AMPLIFIER POWER PER LOUDSPEAKER 500 8500 M 3 4675 72 WATTS 150 WATTS 1000 300 000 FT3 4676A 1 63 WATTS 125 WATTS 14 160 M 3 M676A 2 42 WATTS 100 WATTS 1000 14 160 M 3 4675 90 WATTS 200 WATTS 2000 500 000 FT3 467...

Page 7: ...TS EACH EACH EACH 1000 12 UNITS 38 UNITS 10 UNITS 2000 50 WATTS 5 WATTS 100 WATTS EACH EACH EACH FOR A MAXIMUM LEVEL OF 92 dB FOR A MAXIMUM LEVEL OF 107 dB BOTH 4401 AND 8140 SURROUND SYSTEMS SHOULD BE HIGH PASSED AT 40 Hz OR HIGHER TABLE V SUBWOOFER SELECTION DATA NUMBER OF MODULES EFFICIENCY ELECTRICAL POWER INPUT ACOUSTIC POWER SOUND LEVELS 500 1000 1000 SEATS 2000 SEATS 1 2 300 WATTS 6 WATTS 1...

Page 8: ... FIGURE 5 POSITIONING LOUDSPEAKERS BEHIND THE SCREEN 2 3 T 1 3 i r 1 A SIDE VIEW L_J CT m i I I i B TOP VIEW FIGURE 6 SURROUND SYSTEM IMPLEMENTATION ...

Page 9: ...FIER MAKE SURE AMPLIFIER HAS ADEQUATE POWER OUTPUT 200 MM 8 LOUDSPEAKERS USED IN MULTIPLE 70 VOLT CONFIGURATION JBL 9315HT EACH LOUDSPEAKER TAPPED AT 5 WATTS FIGURE 6 CONT D ELECTRICAL CONSIDERATIONS 8 UNITS 12 UNITS 4X2 LEFT SIDE RIGHT SIDE 5 30 LEFT SIDE RIGHT SIDE ...

Page 10: ... 15 METERS 50 RELATIVE HUMIDITY SCREEN LOSSES 15 MIL THICK VINYL 8 OPENING FIGURE 7 RESPONSE IN THE HOUSE FIGURE 8 ISO STANDARD PLAYBACK RESPONSE dB RELATIVE LEVEL dB RELATIVE LEVEL dB RELATIVE LEVEL SUM OF CURVES A B AND C dB RELATIVE LEVEL DATA FROM FIGURE 7 ...

Page 11: ...25H Low Frequency Transducer 1 2370 High Frequency Horn 1 2425J High Frequency Driver 1 311 OA Network 1 4560BKA Low Frequency Enclosure 1 2225H Low Frequency Transducer 1 2380 High Frequency Horn 1 2445J High Frequency Driver 1 3115A Network 1 4508 Low Frequency Enclosure 2 2225J Low Frequency Transducers 1 2360 High Frequency Horn 1 2445J High Frequency Transducer 1 2506 Mounting Bracket 1 3152A...

Page 12: ...J Wiring Diagram for 4671 4672A 4673 4674 K Wiring Diagram for 4670A 4675A 4676A 1 FIGURE 9 CONT D 2225H ...

Page 13: ...te Splay each HF Horn 22 1 2 off center Total Splay angle of 45 FIGURE 9 CONT D FIGURE 10 LF ENCLOSURE ASSEMBLY INSTRUCTIONS 3 1 5 2 A A MOUNTING LF TRANSCLUCERS IN 4507 4508 AND 4518 B MOUNTING LF TRANSDUCERS IN 4550BKA AND 4560BKA ...

Page 14: ...HORN DRIVER SCREWED IN PLACE BI RADIAL HORN 4 WOOD SCREWS INTO FRONT EDGE OF LF ENCLOSURE LFENCLOSURE FIGURE 11 MOUNTING HORNS IN THEATER SYSTEMS ANGLE IRON PANEL REMOVED 2506 ADAPTER HF DRIVER ...

Page 15: ...FIGURE 12 MOUNTING NETWORKS INCLUDED WITH NETWORK INSERT T NUTS 6 SCREWS TERMINAL BOARD PLATE REMOVED FROM INSIDE ...

Page 16: ...JBL Incorporated RO Box 2200 8500 Balboa Boulevard Northridge California 91329 U S A ...

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