Summary of CINEMA SOUND SET UP
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C i n e m a s o u n d s y s t e m m a n u a l january, 1998.
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Jbl cinema sound system manual table of contents i. Introduction.. .................................................................................................. Ii. Basic system concepts.. .............................................................................. A. Analog film formats.. .....
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Introduction the decade of the 1980’s saw many improvements in the quality of cinema sound. Dolby laboratories had begun the cinema sound revolution during the middle 1970’s with the introduction of noise reduction and equalization of cinema loudspeaker systems. In 1981, jbl demonstrated the first f...
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Loudspeakers. Options are to use the two remaining magnetic tracks for subwoofer signals and/or split (dual channel) surrounds. The 35 mm format was modified during the 1950’s to handle four magnetic tracks: three screen channels and a single surround channel. At the same time, the standard monophon...
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I n p u t s - - - - lt m a s t e r c adaptive matrix level control surrounds i 0 subwoofer audio delay l o w - p a s s filter nr decoder figure block diagram of the dolby stereo optical playback matrix today, the dolby stereo optical system is virtually a standard format on non-digital 35 mm film. I...
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100 hz. This is commonly referred to as a channel system and uses an elaborate perceptual encoding process known as ac-3. Data optical tracks and picture figure 3a. Dolby sr-d figure dts figure 3c. Sdds figure 3b shows the format used in dts. Here we see only the stereo optical tracks and a sync cha...
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Signal out film solar p r e a m p noise ‘ i ’ i cell reduction lamp figure 4a. Block diagram of analog a-chain signal out figure block diagram of digital a-chain screen channel master fader surround channel 1 3 octave sub channel figure 4c. Block diagram of b-chain with split surrounds.
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The b-chain is comprised of one-third octave equalization, dividing networks (low- or high-level), power amplification, and loudspeakers. Jbl professional products are used extensively used in the chain of the system. D. Evolving dynamic range requirements in the cinema figure 4d shows details of th...
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Differences between high and low frequency sections. The chief weakness of these systems was their lack of uniform coverage. System design stressed output conversion efficiency, because of the small power amplifiers available at the time. Figure shows the on- and off-axis curves of a typical horn/re...
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F. Power response and power-flat systems the discrepancy between on-axis and reverberant room response in the older systems was solved with the introduction of a new family of systems based on uniform coverage high-frequency horns and simple ported low-frequency enclosures. Figure 6a shows the horiz...
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When the system described above is equalized in a typical cinema environment, both direct sound and reverberant sound can be maintained quite smoothly, as shown in figure 7a. The system’s reverberant response is proportional to its power output, or to its power response, and the matching of the syst...
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Screen systems. Measurements made at the goldwyn theater of the academy of motion picture arts and sciences in beverly hills, california, show that, over most of the frequency range, front-to-back levels in the house are maintained within a range of 5 by contrast, aiming the high-frequency elements ...
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The surround ensemble of loudspeakers, if properly specified, can easily produce a sound field that is uniform throughout the back two-thirds of the house, and level variations can often be held within a range of 2 to 3 details of surround system specification will be covered in a later section. Whe...
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Acoustical engineers make use of what are called noise criterion (nc) curves in attempting set a noise performance goal for cinemas. The octave band values of these curves are shown in figure 9. In implementing this data, the acoustical designer settles on a given criterion and then determines the c...
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Frequencies tends to lower the reverberation time. Figure 11 shows the normal range of reverberation time, as a function of the value at 500 hz, while figure 12 shows the acceptable range of reverberation at 500 hz as a function of room volume. Variation of tion time with frequency 0.1 12. Suggested...
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C. The role of the acoustical consultant an acoustical consultant should be chosen on the basis of previous jobs well done. There is much that is learned simply by having encountered and solved many problems. Stating it another way, an experienced consultant has probably seen most of the common mist...
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Both systems are capable of the same acoustical output, inasmuch as they are both limited by the power handling capabilities of their identical low-frequency sections. Table 1 indicates the sustained maximum sound pressure level in the reverberant field which these systems can produce, based on room...
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For spaces of 2700 or greater, jbl recommends that the model 4675c be specified in biampiified mode. Cu. Ft.) 111 cu. Ft.) . _ table maximum reverberant for jbl systems in large cinemas mode). B. Advantages of biamplification the importance of biampiification in large cinemas cannot be overestimated...
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D. New jbl driver developments our studies have indicated that, in passive systems, maximum power input to the screen loudspeakers is essentially network limited. As a result of this, many cinema applications ordinarily will not require the high power vented gap performance designed into the jbl 222...
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14. Complete system assembly diagram for 46700 and 46756..
Page 21: Component Exploded View
Component exploded view hiih gasket 20810 bracket inner driver/horn sale) binding red. Blk, 33751 blk bracket outer mounting base (not for assembly hardware kit 72110
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Exploded view horn 2370a 6486641 kit 55343 tube 57932 (not for sale) gasket, vinyl 34499 mounting with kit 55340 cabinet 4507 63299 (not for.
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Exploded 2380a 64889 port tube 57932 (not for sale) view high freq hardware installation kit 57538 support 80851 use mounting hardware included with unit network 47031 mounting hardware included with installation kit 55343 gasket, 34499 cabinet 4507 63299 for sale) hardware included kit 55340
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Figure 18 component exploded gasket view hiih bolt (4) 60703-01 washer 2-114 post adapter 60705 bracket mounting hardware 72144 nut lockwasher washer.
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Figure exploded (4) port tube (2) 56144 for sale) gasket (2) 34499 low freq (2) cone threaded (16) flhd ph.
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Figure 20 network flange right side of lf enclosure 46700 wiring diagram 4671 wiring diagram from 0 amplifier hf driver lf 46738 wiring diagram 4675c wiring diagram amplifier + hf red black red amplifier note: as shown provide eia polarity..
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F. Subwoofers subwoofers are an integral part of cinema loudspeaker systems installed in mid- and large-size houses. In specifying them, the designer must take into account the reduced sensitivity of the ear to low frequency sounds. Figure 21 shows the robinson-dadson equal loudness contours. Note t...
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When the proper room volume has been determined, the designer then can go to the following table and pick the required quantity of subwoofer modules that will ensure the needed acoustical power output: number of 2242 1 4 16 2 6 64 4 12 192 8 16 6400 table 3: nominal efficiency and acoustical power o...
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Exploded view tube for jbl 4645b 60669-01 screw 65555 2242hpl.
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G. Surround requirements as a general rule, the total ensemble of surround loudspeakers should be capable of producing as much acoustical power as a single screen channel. Today, the new jbl 8340 surround loudspeaker is capable of producing total acoustical power output in the range of about 2 watts...
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For digital cinemas with two (“split”) surround channels, we recommend that the minimum number of loudspeakers per channel be set at 8, making a total of 18 loudspeakers. A series-parallel hook-up will be useful for each surround channel. Specific power requirements for the surround channels will be...
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In mid-size screening rooms there is less air loss to deal with, and it is often the case that no more than a 1 boost is required to meet the equalization requirements above 10 many conservative engineers feel that a boost should never be exceeded. Use of multiple high frequency elements in some ver...
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Lumber bracing . . Figure 25. Isometric view of a figure 26. Wings between screen loudspeakers. When possible, large wings should be mounted between systems, as shown in figure 26. The surfaces should ideally be finished with sound absorptive material, any exposed wall areas behind the screen should...
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D . Surround mounting the jbl 2502 mounting bracket will accommodate both the 8330 and the 8340 surround systems. The user has a choice of mounting the loudspeakers for horizontal projection or for downward projection. The electrical response switch on the 8330 and 8340 surrounds should be placed in...
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Figure exploded screw no. 6 x flhd 100” blk horn/driver jbl8340 (not for sale) speaker, low freq screw (4) 67375 no. X flhd ph blk n o . 8 1 pnhd ph blk t-nut (8) screw (8) bthd hex blk.
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A. Wiring for non-biamplified installations all wiring diagrams shown thus far in this manual are for non-biamplified, single amplifier application. Care should be taken that all connections are properly served with tinned wires or spade lugs, if required. The wire should be chosen on the basis of t...
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Figure 30. Typical passive network cinema system of four to six in 3 1. Typical cinema system 1.
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C. Wiring for surround channels jbl recommends that a stereo amplifier be used for surround power, whether or not split surrounds will be used. The reason is simply that this will generally result in better loudspeaker matching as well as facilitating eventual split surround usage. If there are twel...
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D. Wire gauges and line loss calculations good engineering practice requires that line losses result in no greater than a level loss of 0.5 at the load. In making the calculations to determine the smallest wire gauge that will ensure adherence to this, the engineer must keep in mind that the loss at...
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The cutoff slope of a network is defined by its order. For each degree of order, the cutoff rate is 6 thus, a third order network will provide transitions in the crossover range of 16 and a fourth order network will provide transitions of 24 the most common mistake made in field assembly of non-biam...
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0 -10 -70 -100 0 -10 -20 -40 -60 -70 figure 35. Gain-loss diagram for the b-chain of a cinema system note that the gain-loss diagram for this system indicates clearly maximum output levels of each component in the system as well as the noise floor of each component. The goal in proper systems engine...
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1. 2. 3. 4. 5. 7. 8. J. Lansing and j. Hilliard, ‘an improved loudspeaker for theaters,’ journal smpte, vol. 45, pp. 339-349 (1945). References m. Engebretson and j. Eargle, “cinema sound reproduction systems: technical advances and system design considerations,’ journal smpte, vol. 91, no. 11 (nove...
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Jbl professional 8500 balboa boulevard california 91329 usa h a company @copyright 1998 jbl professional printed in usa.