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JBL 300 Series Manual

Other manuals for 300 Series: User Manual, Quick Start Manual
Manual is about: JBL Cinema 300: User Guide

Summary of 300 Series

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    Cinema sound system manual.

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    2 jbl 2003 cinema sound system manual table of contents: i. Introduction ..........................................................................................................................3 ii. Basic systems concepts ...............................................................................

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    3 jbl 2003 cinema sound system manual i. Introduction the decade of the 1980’s saw many improvements in the quality of cinema sound. Dolby laboratories began the cinema sound revolution during the middle 1970’s with the introduction of noise reduction and equalization of cinema loudspeaker systems t...

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    4 intended primarily for the left and right screen loudspeakers are fed to the left and right channels. Program material intended for the center screen loudspeaker, including most on-screen dialog, is fed to both stereo channels in phase. The in-phase relationship between the stereo channels trigger...

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    5 b. Digital film formats the dolby sr-d format, introduced in 1992, is shown in figure 3a. It has exactly the same optical sound tracks as shown in figure 2a with the addition of digital information located in the otherwise unused space between sprocket holes. This new digital format provides the u...

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    6 figure 4: analog a-chain (a); digital a-chain, dolby sr-d (b); digital b-chain, dts (c); block diagram of b-chain with split surrounds (d); dynamic range requirements for dolby a, dolby sr and and dolby digital formats (e).

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    7 d. Evolving dynamic range requirements in the cinema: figure 4e shows details of the headroom capabilities of cinema sound formats. The reference level of dialog in the cinema is 85 db-a, while added headroom is used primarily for more realistic peak levels for sound effects and music. Depending o...

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    8 to frequency. The need for equalization of the compression driver comes as a result of the natural high frequency roll-off, which occurs in high frequency drivers above about 3.5 khz. This frequency is known as the mass break point and is a function of diaphragm mass and various electrical and mag...

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    9 this performance is seen in figure 7. At 7a we show in plan view the direct field coverage given by the center channel jbl 5674 system aimed at the audience approximately two-thirds from front to back, with coverage at 2 khz maintained within a range of ± 4 db overall. A side section view of the t...

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    10 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 db. Details of surround system specification will be covered in a later secti...

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    11 the isolation task is certainly easier with new construction, since buffer areas can be designed between adjacent exhibition spaces. The most difficult problems occur when older spaces are to be subdivided to make multiplex cinemas, inasmuch as the chances of coupling through walls or through com...

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    12 in most cinemas constructed today, echo problems can generally be dealt with by ensuring that the back wall is very absorptive and that substantial damping is installed behind the screen on the baffle-wall. C. The role of the acoustical consultant: an acoustical consultant should be chosen on the...

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    13 loudspeakers is not justified. We will therefore use inverse square calculations in determining loudspeaker levels in the cinema. Because of their frequency range and low directivity, subwoofer calculations can be made taking into account total room volume. Guidelines for digital films state that...

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    14 the 5000 series three-way loudspeakers were developed over an intensive two year period, with much of the later work done at the academy of motion picture arts and sciences, in beverly hills, california, with technical input from the academy theater standards committee, which includes many of hol...

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    15 figure 13: drawings of 3000 series screen systems. Front and side drawings of 3622n (a) and 3678 (b) figure 14: 4000 series screen systems. Perspective and side drawings of 4670d figure 15: drawings of 4000 series screen systems. Front and side drawings of 4622n figure 16: 4000 series screen syst...

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    16 figure 18: 5672 screen system, front and side views. Figure 19: 5674 screen system, front and side views. Figure 20: robinson-dadson equal loudness contours..

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    17 d. Mechanical details of jbl screen loudspeaker systems: most jbl screen channel systems are intended for field assembly, and instructions for their assembly are contained in the shipment. Here, we will show assembled and dimensioned line drawings in front and side views so that the user can dete...

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    18 figure 24 shows mechanical views of the 3635 subwoofer, which is intended for use with the other models in the 3000 series product group. The 3635 subwoofer has a useful lower frequency limit of 28 hz (- 3 db), as compared to 18 hz for the 4645c. The power rating of the 3635 subwoofer is 300 watt...

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    19 g. Screen losses: through-the-screen losses are complex to analyze in detail. The on-axis loss is approximately a 6 db/ octave rolloff commencing at about 5 khz. However, off-axis response is quite different. At certain angles, high frequencies are transmitted through the screen with relatively l...

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    20 figure 26: screenarray loudspeakers. Front (a) and side (b) views of model 4632; front (c) and side (d) views of model 3632..

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    21 v. Mounting requirements a. General comments: the following rules generally apply to screen loudspeakers: 1. They should be positioned vertically so that the horns are about two-thirds the height of the screen. 2. They should be placed so that the horn flanges are within a distance of 5 to 7 cm (...

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    22 b. Screen loudspeaker aiming: if a thx ® system is specified, all details of the vertical baffle wall (or bafflette construction) will be taken care of. Where there is no such specification, the installer will have to construct one large platform, or a number of smaller ones, depending on costs. ...

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    23 since early 1999, an improvement in surround technology known as surround ex uses a variation on matrix methods to produce a rear surround channel. When this option is called for, the surrounds will have to be reallocated electrically from the booth, as shown in figure 32. Dolby laboratories has ...

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    24 when completely new product groups or model numbers are introduced, jbl is in compliance with the eia standard. When older products are modified with no change in the basic model number, or where new products will be required to interface with older ones, jbl usually maintains the negative conven...

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    25 d. Wiring diagrams for 5000 series screen systems: the three models in the 5000-series are always triamplified. Models 5671 and 5672 all use three power amplifier sections, while the 5674, due to the quadruple set of lf units, makes use of four amplifier sections. All aspects of frequency divisio...

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    26 e. Wiring diagrams for screenarray systems: the model 3632 wired for biamped operation is shown in figure 36a. The model 4632 is shown biamped in figure 36b; triamped wiring of the 4632 is shown at 36c. Figure 35: wiring diagram for 5000-series systems. 5671 and 5672 (a); 5674 (b).

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    27 f. Surround wiring diagrams: jbl strongly recommends that each surround loudspeaker be individually wired back to the projection booth, and that any paralleling of loudspeaker loads be made at that location. In general, we recommend that no more than a single pair of sound loudspeakers be paralle...

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    28 figure 37: typical stereo surround hookup. Figure 38: surround-ex hookup..

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    29 g. Subwoofers: the general rule here is one amplifier section to one subwoofer driver, as in the case of the 4641 and 4645c models. The model 4642a contains two 2441h drivers connected in parallel resulting in a 4-ohm load. This system is intended for use in those installations that require multi...

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    30 figure 39: level diagram for 5674 (lf section)..

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    31 vii. Summary of recommendations for selecting and installing theater loudspeaker systems a. Specifying and installing screen channels: the following recommendations will give the reader a quick reference guide for specifying and installing loudspeakers in all cinema applications. These recommenda...

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    32 b. Specifying and installing surround channels: 1. Surround channel assumptions: • moderate power surrounds (cone/dome): sensitivity: 91 db spl, 1 w at 1 m, typical; power rating: 100 watts continuous. • high power surround (hf horn): sensitivity 96 db spl, 1 w at 1 m, typical; power rating: 250 ...

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    33 8. Selecting surround amplifiers: • choose stereo amplifiers with a generous 4-ohm power rating equal to twice the individual surround loudspeaker power rating. • for example, using high power surrounds, select a stereo amplifier that can deliver 500 watts into four ohms. 9. If you have followed ...

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    34 4. Subwoofer mounting: • mount the subwoofers at the base of the screen and as close as possible to the wall/floor intersection. • cluster the individual units together in order to take maximum advantage of mutual coupling. • watch out for rattles; use plenty of neoprene padding for isolation. (s...

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    35 xi. Loudspeaker signal processing for jbl dsc260a the following loudspeaker signal processing settings are intended for the jbl dsc260a digital system controller. Different loudspeaker controllers may have channel-to-channel differences in delay settings. They may also have different definitions ...

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    36 speaker system: 4675c-4lf date: 3/4/2003 dsc260 parameter input a input b input a+b input delay input eq1 type input eq1 frequency input eq1 +/- input eq1 bandwidth input eq2 type input eq2 frequency input eq2 +/- input eq2 bandwidth input eq3 type input eq3 frequency input eq3 +/- input eq3 band...

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    37 speaker system: 4675c-8lf date: 3/4/2003 dsc260 parameter input a input b input a+b input delay input eq1 type input eq1 frequency input eq1 +/- input eq1 bandwidth input eq2 type input eq2 frequency input eq2 +/- input eq2 bandwidth input eq3 type input eq3 frequency input eq3 +/- input eq3 band...

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    38 speaker system: screenarray tm 4622 (bi-amp) date: 3/4/2003 dsc260 parameter input a input b input a+b input delay input eq1 type bell* bell* input eq1 frequency 50.7 50.7 input eq1 +/- 3.0 3.0 input eq1 bandwidth 0.60 0.60 input eq2 type input eq2 frequency input eq2 +/- input eq2 bandwidth inpu...

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    39 speaker system: screenarray tm 3632 (bi-amp) date: 3/4/2003 dsc260 parameter input a input b input a+b input delay input eq1 type bell* bell* input eq1 frequency 50.7 50.7 input eq1 +/- 3.0 3.0 input eq1 bandwidth 0.60 0.60 input eq2 type input eq2 frequency input eq2 +/- input eq2 bandwidth inpu...

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    40 speaker system: screenarray tm 3632-t (tri-amp) date: 3/4/2003 dsc260 parameter input a input b input a+b input delay input eq1 type bell* bell* input eq1 frequency 50.7 50.7 input eq1 +/- 3.0 3.0 input eq1 bandwidth 0.60 0.60 input eq2 type input eq2 frequency input eq2 +/- input eq2 bandwidth i...

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    41 speaker system: screenarray tm 4632 (bi-amp) date: 3/4/2003 dsc260 parameter input a input b input a+b input delay input eq1 type bell* bell* input eq1 frequency 50.7 50.7 input eq1 +/- 3.0 3.0 input eq1 bandwidth 0.60 0.60 input eq2 type input eq2 frequency input eq2 +/- input eq2 bandwidth inpu...

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    42 speaker system: screenarray tm 4632-t (tri-amp) date: 3/4/2003 dsc260 parameter input a input b input a+b input delay input eq1 type bell* bell* input eq1 frequency 50.7 50.7 input eq1 +/- 3.0 3.0 input eq1 bandwidth 0.60 0.60 input eq2 type input eq2 frequency input eq2 +/- input eq2 bandwidth i...

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    43 dsc recommended settings cinema 5000 march 23, 1999 system output 5674 5672 5671 delay ms a subs 0.000 0.000 0.000 b lows 1.656 1.656 1.604 c mids 0.000 0.000 0.000 d highs 1.854 1.854 1.739 polarity [+] unless noted eq a1 frequency (hz) subs not used not used not used bandwidth in octaves db a2 ...

  • Page 44: Jbl Cinema - Product Line

    44 cross reference of jbl cinema speakers to crown power amplifier s. Screenarray series good better crossover option for cl amplifiers best crossover option for cts amplifiers model; description: nom. Imp: system power handling: 3622n 2-way passive 400 watt (thru network) xls402 cl2 na cts600 i...

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    45 ix. References and additional reading: 1. J. Lansing and j. Hilliard, “an improved loudspeaker for theaters,” journal smpte, vol. 45, pp. 339-349 (1945). 2. M. Engebretson and j. Eargle, “cinema sound reproduction systems: technical advances and system design considerations,” journal smpte, vol. ...

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    ©copyright 2003 jbl professional revised 6/11/03 jbl professional 8500 balboa boulevard northridge, california 91329 usa.