Dolby Laboratories CP650 User Manual

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Page 1

Model CP650

Digital Cinema Sound Processor

Installation Manual

Issue 4 Part No. 91569

Page 2

Dolby® Model CP650 Installation Manual

Dolby Laboratories, Inc.

Corporate Headquarters

Dolby Laboratories, Inc.

100 Potrero Avenue San Francisco, CA 94103-4813

Telephone 415-558-0200 Fax 415-863-1373

www.dolby.com

European Headquarters

Dolby Laboratories, Inc.

Wootton Bassett Wiltshire, SN4 8QJ, England

Telephone (44) 1793-842100 Fax (44) 1793-842101

Dolby and the double-D symbol are registered trademarks of Dolby Laboratories. Auditorium Assist, EQ Assist, and Surround EX are trademarks of Dolby Laboratories. All other trademarks remain the property of their respective owners.

Part No. 91569

S02/14315/14409

Software Version 2.1.x.x

Issue 4

Page 3

List of Figures........................................................................................................vii

List of Tables..........................................................................................................ix

CP650 Operating System Software History............................................................x

Chapter 1 Introduction

1.1 About the Dolby CP650 Digital Cinema Processor .................................1-1

1.2 Hardware Configurations Available.........................................................1-2

1.3 Accessories...............................................................................................1-3

1.4 Dolby Catalog Number Listing ................................................................1-3

1.5 Specifications ...........................................................................................1-3

1.6 About Dolby Digital Surround EX...........................................................1-6

1.7 List of Formats Available.........................................................................1-8

1.8 How to Identify Types of Soundtracks.....................................................1-9

1.9 Regulatory Notices.................................................................................1-10

Dolby® Model CP650 Installation Manual

Table of Contents

Chapter 2 Installation

2.1 Replacing an Existing Sound System.......................................................2-1

2.1.1 Before Playing the Film:.............................................................2-1

2.1.2 While Playing the Film:..............................................................2-1

2.1.3 Disconnect the Old System.........................................................2-2

2.2 Check Fuse and Bypass Mains Voltage Selector.....................................2-2

2.3 Mount the CP650......................................................................................2-3

2.4 Mount the Auditorium Assist Microphone...............................................2-4

2.5 Connect the CP650...................................................................................2-4

2.5.1 Motor-Start Relays......................................................................2-4

2.5.2 Remote Controls .........................................................................2-5

2.5.3 Solar Cell Reader Boards............................................................2-5

2.5.4 Analog Nonsync Sources............................................................2-8

2.5.5 Digital Audio Sources.................................................................2-8

2.6 Exploded View and Board Locations.....................................................2-12

Wiring Diagram- Input and Control...................................................................2-13

Wiring Diagram- Audio Outputs........................................................................2-14

Wiring Diagram- Audio Outputs forBiamplified Screen Speakers....................2-15

Wiring Diagram- Audio Outputs for Triamplified Screen Speakers..................2-16

System Signal Flow Chart..................................................................................2-17

Chapter 3 Front Panel and Alignment Overview

3.1 The CP650 Front Panel ............................................................................3-1

3.2 The Setup Control Panel...........................................................................3-6

3.3 Power Supply Voltage Test Points...........................................................3-8

3.4 Aligning the B-Chain and A-Chain..........................................................3-8

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Dolby® Model CP650 Installation Manual

Chapter 4 B-Chain Alignment

4.1 Check Theatre Equipment........................................................................4-1

4.2 Microphone Placement.............................................................................4-2

4.3 Initial Setup ..............................................................................................4-3

4.4 SPL (Sound Pressure Level) Calibration..................................................4-4

4.4.1 Initial Setup (CP650s with Cat. No. 791 Crossover)..................4-4

4.4.2 Calibration Procedure (All CP650s)...........................................4-4

4.5 Initial Output-Level Calibration...............................................................4-6

4.5.1 Main Channels ............................................................................4-6

4.5.2 Subwoofer Channel.....................................................................4-8

4.6 Crossover Setup (CP650 with Cat. No. 791)............................................4-9

4.7 Room Equalization.................................................................................4-17

4.7.1 Crossover Level Adjustment (for CP650s with Cat. No. 791) .4-17

4.7.2 Setting Coarse (Bulk) EQ .........................................................4-19

4.7.3 Setting Fine EQ (1/3 Octave)....................................................4-20

4.7.4 The EQ Assist Feature ..............................................................4-22

4.7.5 Setting Subwoofer Channel EQ................................................4-23

4.7.6 Final Output-Level Calibration.................................................4-25

4.8 Final Sound Check: Rotating Pink Noise...............................................4-28

Chapter 5 A-Chain Alignment

5.1 Overview ..................................................................................................5-1

5.2 Reverse-Scan Checkup: Projector ............................................................5-2

5.3 Analog Optical Alignment: Projector.......................................................5-2

5.4 Dolby Level Set........................................................................................5-4

5.5 Film-Path Alignment Check.....................................................................5-6

5.6 Cell Alignment Check..............................................................................5-7

5.7 Cell Wiring Check....................................................................................5-8

5.8 Azimuth Check.........................................................................................5-8

5.9 Focus Check .............................................................................................5-9

5.10 Optical HF Equalization (Slit-Loss EQ).................................................5-10

Chapter 6 Digital Soundheads

6.1 Mechanical Alignment .............................................................................6-1

6.2 Adjustment with Oscilloscope..................................................................6-2

6.3 Focus Adjustment.....................................................................................6-2

6.4 LED Brightness Confirmation and Adjustment .......................................6-3

6.4.1 Inboard Digital Readers ..............................................................6-3

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Dolby® Model CP650 Installation Manual

Chapter 7 Final Adjustments

7.1 Setting Bypass Level................................................................................7-1

7.2 Setting Optical Surround Delay................................................................7-2

7.3 Setting Digital Surround Delay ................................................................7-3

7.4 Setting Dolby Digital Reader Delay.........................................................7-5

7.5 Nonsync Level Adjustment......................................................................7-7

7.6 Mono Level Trim and EQ Adjustment.....................................................7-8

7.7 Assigning Preset Fader Levels .................................................................7-9

7.8 Assigning User Button Formats .............................................................7-10

7.9 Assigning NS Button Format .................................................................7-11

7.10 Format 80/81 PCM Options ...................................................................7-11

7.11 Reversion Mode......................................................................................7-12

7.12 Auto Surround EX Disable.....................................................................7-12

7.13 Noise Gating...........................................................................................7-13

7.14 Running Auditorium Assist....................................................................7-14

7.14.1 Operation...................................................................................7-14

7.14.2 Establish Reference Measurements ..........................................7-15

7.14.3 Auditorium Sound Check..........................................................7-16

7.14.4 “FAIL” Parameters ...................................................................7-17

7.15 Noise Floor Optimization.......................................................................7-18

7.16 Clock Set ................................................................................................7-19

7.17 Date Set ..................................................................................................7-20

7.18 Mute Fade Time Adjustment..................................................................7-20

Chapter 8 Accessories

8.1 Introduction ..............................................................................................8-1

8.2 Cat. No. 779 Remote Control Installation................................................8-2

8.2.1 Remove the Housing...................................................................8-2

8.2.2 Make a Hole for the Interface Cable...........................................8-2

8.2.3 Connect to the Circuit Board ......................................................8-3

8.2.4 Set the Address Switch ...............................................................8-4

8.2.5 Assemble the Unit.......................................................................8-4

8.2.6 Connect to the CP650 .................................................................8-5

8.3 Cat. No. 771 Remote Fader Installation...................................................8-6

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Dolby® Model CP650 Installation Manual

Chapter 9 Maintenance and Troubleshooting

9.1 Print Cleanliness.......................................................................................9-1

9.2 Digital Soundhead Maintenance...............................................................9-1

9.2.1 Replacing the Cat. No. 701 LED Assembly ...............................9-2

9.2.2 Replacing the Cat. No. 700 Exciter Lamp ..................................9-5

9.3 CP650 Troubleshooting............................................................................9-6

9.3.1 Power Supply Voltage Ranges....................................................9-6

9.3.2 Exploded View and Board Locations .........................................9-7

9.3.3 The Event Log.............................................................................9-8

9.3.4 Troubleshooting Chart ................................................................9-8

Wiring Diagram- Power Supply, Black Cover...................................................9-18

Wiring Diagram- Power Supply, Gold Cover....................................................9-18

Exploded Views- Digital Readers ......................................................................9-19

Appendix A Software Operations

A.1 Display Information About This CP650 Unit .........................................A-1

A.2 Updating CP650 Software.......................................................................A-2

A.3 Transferring Settings Between Two CP650s ..........................................A-3

Appendix B Back Panel Connectors

Appendix C Optical Surround Level Trim

Appendix D Format Descriptions

D.1 Channel Definitions.................................................................................D-1

D.2 Format Definitions...................................................................................D-2

Appendix E External Control of CP650

E.1 Control via RS-232 Serial Data Port ....................................................... E-1

E.2 Control via Remotes Connector ..............................................................E-4

Appendix F Setup and User Menus

F.1 CP650 Setup Menu.................................................................................. F-1

F.2 CP650 User Menu ................................................................................... F-4

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Dolby® Model CP650 Installation Manual

List of Figures

Figure 1–1 Surround Speaker/Amplifier Switching for 5.1 and Surround EX Modes ................1-7

Figure 1–2 Photograph of Film Soundtracks................................................................................1-9

Figure 1–3 Film Soundtrack Identification ..................................................................................1-9

Figure 2–1 Main Fuse Assembly..................................................................................................2-2

Figure 2–2 Star Washers and Rack-Mounting Screws.................................................................2-3

Figure 2–3 Cell Preamp Wiring Using Two 3-Conductor Shielded (Screened) Cables ..............2-6

Figure 2–4 Cell Preamp Wiring Using One 5- or 6-Conductor Shielded (Screened) Cable........2-6

Figure 2–5 Cell Preamp Wiring Using Two 2-Conductor Shielded (Screened) Cable................2-7

Figure 2–6 Cell Preamp Wiring Using One 4-Conductor Shielded (Screened) Cable ................2-7

Figure 2–7 Cat. No. 790 S/PDIF Connections.............................................................................2-9

Figure 2–8 Cat. Nos. 794/778 AES/EBU and S/PDIF Jumper Selections and Connections.......2-9

Figure 2–8 Model CP650 Exploded View .................................................................................2-12

Wiring Diagram- Input and Control...........................................................................................2-13

Wiring Diagram- Audio Outputs................................................................................................2-14

Wiring Diagram- Audio Outputs forBiamplified Screen Speakers............................................2-15

Wiring Diagram- Audio Outputs for Triamplified Screen Speakers..........................................2-16

System Signal Flow Chart..........................................................................................................2-17

Figure 3–1 Front-Panel Controls..................................................................................................3-1

Figure 3-2 Front-Panel Display Showing All Possible Channels Active.....................................3-2

Figure 3-3 Front-Panel Display Showing a Dolby Digital Film Playing.....................................3-3

Figure 3-4 Front-Panel Display Showing Dolby Digital Surround EX Film Playing..................3-3

Figure 3-5 Front-Panel Display When Running Earlier Software ...............................................3-3

Figure 3–3 Fader Characteristic ...................................................................................................3-4

Figure 3–4 CP650 Operation and Setup Menu Control Buttons..................................................3-5

Figure 3–5 Setup Control Panel ...................................................................................................3-6

Figure 3–6 Power Supply Voltage Test Points.............................................................................3-8

Figure 4–1 EQ Microphone Placement ........................................................................................4-2

Figure 4–2 Cat. No. 772A Board Jumpers for Cat. No. 791 Crossover.......................................4-9

Figure 4–3 Cat. No. 791 Board Jumpers for Screen Loss HF Boost............................................4-9

Figure 4–4 EQ Assist Operating Range .....................................................................................4-22

Figure 6–1 Digital Soundhead Adjustments.................................................................................6-1

Figure 6–2 Digital Video Oscilloscope Image—Focus Adjustment............................................6-3

Figure 6–3 Cat. No. 701 LED Brightness Adjustment.................................................................6-3

Figure 8–1 Cat. No. 779 Remote Control Functions....................................................................8-2

Figure 8–2 Location to Drill Wiring Hole....................................................................................8-3

Figure 8–3 Remote-Control Circuit-Board Connector.................................................................8-3

Figure 8–4 SW1 Address Switch Location ..................................................................................8-4

Figure 8–5 Connection of Remotes to the CP650........................................................................8-5

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Dolby® Model CP650 Installation Manual

Figure 9–1 Digital/Analog Track Wear........................................................................................9-1

Figure 9–2 LED Assembly Mounting Screws..............................................................................9-2

Figure 9–3 LED Assembly Wiring...............................................................................................9-2

Figure 9–4 LED Assembly Initial Gap Setting ............................................................................9-2

Figure 9–5 Scope Display of CP650 Video Test Point Signal.....................................................9-4

Figure 9–6 Adjust LED Assembly for Optimum Video Signal ...................................................9-4

Figure 9–7 LED Drive-Current Setting........................................................................................9-4

Figure 9–8 Digital Soundhead Exciter Lamp Replacement.........................................................9-5

Figure 9–9 Power Supply Voltage Test Points.............................................................................9-6

Figure 9–10 Model CP650 Exploded View .................................................................................9-7

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Dolby® Model CP650 Installation Manual

List of Tables

Table 1–1 Formats Supported by the CP650................................................................................1-8

Table 2–1 Solar Cell Preamp Board Connectors..........................................................................2-6

Table 2–2 Examples of Available Balanced ↔↔↔↔ Unbalanced Adapters......................................2-11

Table 7–1 Surround Delays Based on Theatre Dimensions (in Feet) ..........................................7-4

Table 7–2 Surround Delays Based on Theatre Dimensions (in Meters)......................................7-5

Table 7–3 Typical Delay Settings for Dolby Digital Readers......................................................7-6

Table 7–4 Typical Delay Settings for Built-in Digital Readers ...................................................7-6

Table 9–1 Main Power Supply Voltage Ranges...........................................................................9-6

Table 9–2 Bypass Power Supply Voltage Ranges........................................................................9-6

Table B–1 Main Audio Output Connector Pinout.......................................................................B-1

Table B–2 Option Card I/O Connector Pinout with Cat. Nos. 790, 791, or 794 Installed..........B-2

Table B–3 Option Card I/O Connector Pinout with Cat. No. 778 Installed................................B-3

Table B–4 Dolby Digital Reader Input Connector Pinout ..........................................................B-4

Table B–5 Motor-Start Connector Pinout ...................................................................................B-5

Table B–6 Optical Input Connector Pinout.................................................................................B-5

Table B–7 Mic Input Connector Pinout ......................................................................................B-5

Table B–8 MIC MUX Connector................................................................................................B-6

Table B–9 Remote Unit and Remote Fader Connector Pinout ...................................................B-6

Table B–10 Six-Channel Analog Input Connector Pinout..........................................................B-7

Table B–11 Automation I/O Connector Pinout...........................................................................B-8

Table B–12 Automation I/O Connector Pins Used for Noise Gating .........................................B-9

Table B–13 Serial Data (RS-232) Connector Pinout ..................................................................B-9

Table D–1 Channel Definitions...................................................................................................D-1

Table D–2 Format Characteristics Chart...................................................................................D-10

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Dolby® Model CP650 Installation Manual

CP650 Operating System Software History

V1.0.4.4

• First product shipments.

• Covered in Installation Manual, Issue 1.

V1.1.3.0

• Added support for Cat. No. 790 or 794 card: Dolby

decoder and AES/EBU input for stereo pulse-code modulated (PCM) or Dolby Digital bitstreams from consumer products.

• Covered in Installation Manual Addendum, Part No. 91743.

V1.1.5.0

• Added support for Cat. No. 779 remote control unit and Cat. No. 771 remote

fader unit. Covered in Remotes Installation Manual, Part No. 91733.

Digital Surround EXTM

V1.1.7.0

• Added support for formats 92 and 93, Dolby SR input selections.

V1.2.x.y (where x and y may be any numbers)

• Added support for Auto Dolby Digital Surround EX switching, external

control via the RS-232 serial data port, and the rotating pink-noise feature.

• The EQ Assist

feature description was added to the installation manual.

• These features, along with all of the above updates, are covered in Installation

Manual, Issue 2.

V2.0.x.y (where x and y may be any numbers)

• Added the Auditorium Assist

characterization of the audio environment in a theatre, and allows periodic checks and comparisons to qualify the sound system.

feature, which measures and stores a

• Added support for the Cat. No. 778 Eight-Channel Digital I/O Card for use in

mixing studios.

• Added a noise floor optimization feature, which provides automatic gain

adjustments in the equalizers for improved noise performance.

• These features, plus all of the above updates, are covered in this installation

manual.

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Dolby® Model CP650 Installation Manual

V2.1.x.y (where x and y may be any numbers)

• Added support for the Cat. No. 790 Dolby Digital Surround EX

Decoder Card with four S/PDIF digital inputs. This card replaces the Cat. No. 794, adding three additional S/PDIF digital inputs.

• Added support for the Cat. No. 791 Digital Crossover Card. This card plugs

into the Cat. No. 790, providing two- and three-way screen channel crossover capability along with support for Left Extra/Right Extra screen channels.

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Dolby® Model CP650 Installation Manual

Chapter 1

Introduction

1.1 About the Dolby CP650 Digital Cinema Processor

The Dolby CP650 Digital Cinema Processor is a self-contained, all-digital cinema processor capable of supporting Dolby® Digital, Dolby Digital Surround EXTM, Dolby SR, Dolby A-type, and Academy mono film sound playback.

The CP650 provides inputs for two projector soundheads (both analog and digital), an external six-channel processor, two nonsync sources, and a PA microphone. Its audio outputs are balanced, with a multipin connector configured to the THX standard. The CP650 is the first cinema processor to incorporate an Ethernet connection, enabling theatre personnel to monitor the unit’s functions remotely from a PC.

For decoding analog soundtracks, the CP650’s state-of-the art design incorporates the only digital implementations of Dolby A-type and Dolby SR decoding that meet Dolby Laboratories’ own rigorous standards. Reductions in the cost of powerful digital signal processing (DSP) circuitry have made it possible for the first time to replace the analog circuitry previously necessary for the accurate reproduction of A-type and SR soundtracks.

An easy-to-read LCD screen, plus simple front-panel format selection and control buttons, makes it easy to install, operate, and maintain the CP650. Installation is further simplified by built-in test instrumentation that includes a real-time analyzer. Third-octave equalization, plus bass and treble trim controls, are provided for up to seven channels (Left, Center, Right, Left Surround, Right Surround, Back Surround Left, and Back Surround Right). A digital parametric equalizer is provided for subwoofer equalization.

Easily programmed internal software manages most existing or likely future formats. While an external PC is not required for setup, a full-featured software package is available in several languages to facilitate the setup process. A serial connector for a PC, an input for a calibration microphone multiplexer, and a variety of test points are all accessible behind an access door on the front-panel. Built-in diagnostic software runs automatically whenever the CP650 is turned on.

Calibration settings for a given theatre can be stored on a PC, and, if necessary, transferred directly to another CP650, or other modules, minimizing the need for additional calibration after repairs. As improvements to the CP650 digital control and processing software are developed, the latest revisions will be downloadable from a PC to the CP650. Updates to the digital processing used for Dolby Digital soundtracks are included from time to time on Dolby Digital release prints, and

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Dolby® Model CP650 Installation Manual Introduction

download automatically into the CP650 the first time such a print is played in the cinema.

The standard Model CP650 includes a Cat. No. 790 (Cat. No. 794 in earlier units) plug-in module featuring Dolby Digital Surround EX decoding, plus four-input AES/EBU digital inputs accommodating PCM audio and Dolby Digital (consumer) bitstreams.

Options available for the CP650 include a remote fader (Cat. No. 771), a remote unit (Cat. No. 779) that duplicates many of the CP650’s front-panel controls, and an eightchannel digital I/O card for use in mixing studios (Cat. No. 778).

1.2 Hardware Configurations Available

The CP650 is available in these versions:

Model CP650

• Dolby Digital soundtrack decoding

• Dolby A-type and SR analog soundtrack decoding

• Dolby Digital Surround EX decoding

• Four AES/EBU digital inputs

• Up to five AES/EBU digital outputs

• Six-channel analog input

Model CP650D

• Dolby Digital soundtrack decoding

• Dolby A-type and SR analog soundtrack decoding

• Six-channel analog input

• Upgradable to Dolby Digital Surround EX decoding and 4x AES/EBU digital

inputs by installing upgrade kit UEX/650, which includes a Cat. No. 790 plug-in circuit board.

Model CP650SR

• Dolby A-type and SR analog soundtrack decoding capability

• Six-channel analog input

• Upgradable to Dolby Digital soundtrack decoding by adding upgrade kit

UD/650, which includes a Cat. No. 773 plug-in circuit board

• Upgradable to Dolby Digital Surround EX decoding and 4x AES/EBU digital

inputs by installing upgrade kits UD/650 and UEX/650 (which includes a Cat. No. 790 plug-in circuit board)

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Dolby® Model CP650 Installation Manual Introduction

1.3 Accessories

• Upgrade kit UD/650, which includes the Cat. No. 773 circuit board

• Upgrade kit UEX/650, which includes the Cat. No. 790 circuit board

• Upgrade kit Cat. No. 735 Auditorium Assist

, which includes a microphone

• Cat. No. 771 Remote Fader

• Cat. No. 778 Digital I/O Board, which provides up to eight channels of digital I/O

• Cat. No. 779 Remote Control Unit

• Upgrade Kit Cat. No. 791 Digital Crossover, which provides two-way or three-

way screen-channel crossover capability

1.4 Dolby Catalog Number Listing

Cat. No. 771 Remote Fader Cat. No. 772A Analog I/O and Bypass Circuit Board Cat. No. 773 Dolby Digital Film Decoder Circuit Board Cat. No. 774A System Controller Circuit Board Cat. No. 775 Backplane Board Cat. No. 776 Power Supply Assembly Cat. No. 777 Front-Panel Circuit Board Cat. No. 778 Digital I/O Board Cat. No. 779 Remote Control Unit Cat. No. 790 Dolby Digital Surround EXTM Decoder with Four Digital Inputs

(this board replaces the earlier Cat. No. 794) Cat. No. 791 Crossover Board (Cat. Nos. 773, 790, 772A, and 774A required) Cat. No. 792 Bypass Power Regulator Circuit Board Cat. No. 794 Dolby Digital Surround EX Decoder with Digital AES/EBU Input

Board (used in earlier CP650s; replaced by Cat. No. 790) Cat. No. 797 Flash memory module (part of the Cat. No. 774A board)

1.5 Specifications

Signal Inputs

Optical: Balanced inputs for two projectors with stereo solar cells or analog LED readers, digitally controlled gain and digital slit-loss EQ, power available for external cell preamp circuits; 9-pin D-connectors

Digital film reader: Inputs for two Dolby digital soundheads; 25-pin D-connectors

Nonsync: Two stereo inputs, 21 kΩ, sensitivity: 0.2–4 V (NS 1),

0.06–1.5 V (NS 2); RCA-type phono connectors

Six-channel analog input: For external digital processor, 10 kΩ (L, R), 27 kΩ (C, Ls, Rs, SW), 300 mV operating level; 25-pin D-connector

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Dolby® Model CP650 Installation Manual Introduction

Microphone: Balanced input for Auditorium Assist microphone, PA mic, or B-chain alignment mic (or multiplexer), 15 V phantom power switchable via front-panel DIP switch; rear-panel XLR and front-panel 9-pin D-connector

AES/EBU digital inputs: Accommodate stereo PCM audio at 48, 44.1, or 32 kHz, also accept Dolby Digital bitstreams; input via 25-pin D-connector with optional adapter boards (Cat. Nos. 790 or 778) 110Ω ±20%, balanced (equipped with Cat. No. 778, four inputs), or 75Ω ±20%, single-ended (equipped with Cat. No. 790, four inputs)

Signal Outputs

Balanced, output impedance: 100Ω (load >600Ω) Maximum level: +26 dBu (15.5 V), balanced loads; +20 dBu (7.75 V), unbalanced loads Dolby level output adjust range: –31 to –12 dBu (20–780 mV)

Other Connections

Cat. No. 779 remote control unit and Cat. No. 771 remote fader connector (terminals for stripped wires)

Connectors (front and rear) for external PC control and setup, RS-232C (9-pin D-connector)

Hearing-impaired output: Center-weighted sum of L, R, and C; output impedance 100Ω, output level 200 mV fixed; unbalanced (RCA-type phono connector)

Automation connector for controlling and indicating format, fader select, and mute; interface similar to Model CP65

Connector for Ethernet link, RJ-45

Dolby Decoding

5.1 channels: Dolby Digital and Dolby Digital Surround EX Four channels: Dolby A-type Two channels: Dolby SR Dolby Pro Logic

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Dolby® Model CP650 Installation Manual Introduction

Loudspeaker Equalization

L, C, R, Ls, Rs, Bsl, Bsr: Digital 27-band, 1/3-octave, plus bass and treble control Le, Re (when equipped with optional Cat. No. 791): Digital 27-band, 1/3-octave, plus bass and treble control SW: Digital parametric with 12 dB cut capability

Distortion

Typically 0.005% in Dolby SR mode (output –10 dBu, input 10 dB over Dolby level)

Dynamic Range

Typically 99 dB with fader set to 7

Power Requirements

Main supply: 100–120 and 200–240 VAC, 50–60 Hz, 100 W maximum (including built-in bypass power supply) Unit designed to operate from a centrally switched power source

Dimensions and Weight

3-U rack-mount chassis; faceplate: 133 × 483 mm (5.25 × 19 inches) Maximum projection behind equipment rack rail: 365 mm (14.4 inches) Maximum projection in front of mounting plate: 38 mm (1.5 inches) Net: 10.4 kg (23 lb)

Environmental Conditions

Operating: 0° to 40°C (32° to 104°F), forced-air cooling Humidity: 20 to 80% relative humidity, noncondensing

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Dolby® Model CP650 Installation Manual Introduction

1.6 About Dolby Digital Surround EX

Dolby Digital Surround EX adds a third surround channel to digital film sound, a concept first envisioned by sound designers at Lucasfilm’s Skywalker Sound postproduction facility. It gives sound mixers a new level of creative freedom.

Dolby Digital Surround EX is fully compatible with all current 5.1 digital sound formats and theatre systems. Prints that use it play normally with current systems, and provide the extra surround channel when played using a CP650 cinema processor equipped with a Cat. No. 790 or 794 board.

A center screen channel is necessary to ensure the precise localization of front sounds for all viewers, including those seated off to the sides. Dolby Digital Surround EX brings similar benefits to the surround sound field. With Surround EX, a back surround channel is reproduced by the speaker array at the back of the theatre, while left and right surround is reproduced by the side arrays. This means that sounds can now be positioned behind the audience, opening the door to exciting new effects, such as true 360-degree pans.

The back surround channel also makes front-to-back and back-to-front transitions more realistic. Flyovers really seem to pass overhead, rather than down the sides of the theatre. Even ambient sound reproduction is improved, being less affected by the width of the theatre. Equally important, the new back surround channel ensures that even viewers seated close to the left or right of the theatre experience the total surround ambience intended by the filmmaker.

The UEX650 kit upgrades the CP650D 5.1-channel digital cinema sound processor to three surround channels that can play digital prints prepared with the Dolby Digital Surround EX process. The installation requires wiring the surround speakers into left, back (split into two groups), and right. Two power amplifier channels are required for powering the two groups of back surround channel speakers. The figures below show the surround signal distribution for conventional the 5.1-channel surround format and for the Dolby Digital Surround EX format.

Auto Surround EX

On Dolby Digital soundtracks that contain a data bit signifying Surround EX encoding, the CP650 will automatically switch to Dolby Digital Surround EX decoding (operating software version 1.2 and above).

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Dolby® Model CP650 Installation Manual Introduction

Right surround

Dolby CP650

Ls Bsl Bsr Rs

Surround amplifiers

Ls Bsl Bsr Rs

Left surround

Back surround left

Back surround right

Dolby Digital

5.1 mode

Right surround

Dolby CP650

Ls Bs Rs

Ls Bsl Bsr Rs

Surround amplifiers

Ls Bsl Bsr Rs

Left surround

Back surround left

Back surround right

Dolby Digital Surround EX mode

Figure 1–1 Surround Speaker/Amplifier Switching for 5.1 and Surround EX Modes

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Dolby® Model CP650 Installation Manual Introduction

1.7 List of Formats Available

The formats supported by the CP650 are listed below. See Appendix D for complete definitions of each format.

Table 1–1 Formats Supported by the CP650

Format Description Short Name

01 04 05 10 11 13 20 22 42 60 61 64 65 66 70 71 73 74 75 80 81

87 88 89 90 92 93

Academy mono optical Mono Dolby A-type optical Dolby A-type Dolby SR optical Dolby SR Dolby Digital film Dolby Digital External six-channel Dolby Digital Surround EX film Surround EX 35 mm magnetic, L, C, R three-channel Three-channel mag 35 mm magnetic, four -c hannel Four-channe l ma g 70 mm Dolby A-type mag. mono surround 70 mm Dolby Stereo Nonsync 1 Nonsync 2 Public-address center channel Public address, C Public Address Surround Channels Public address, LsRs Test Tone 320 Hz Video PA Nonsync 1 Video PA (NS1) Video mono Nonsync 1 Video Mono (NS1) Video LCR Nonsync 1 Video LCR (NS1) Video Pro Logic no SW Nonsync 1 Vid Pro Logic no SW Video Pro Logic with SW Nonsync 1 Vid Pro Logi c +SW Bitstream Master Digital Input Master Digital In Bitstream Master Digital + Surround EX Fmt 80 w/Surr. EX

Bitstream PCM Eight-Channel Input, Ten-Channel Output (Le/Re Support)

Bitstream PCM Eight-Channel Input, Ten-Channel Output + Surround EX (Le/Re Support)

Ext. Six-Channel with Surround EX Fmt 11 w/Surr. EX Six-Channel PCM Six-Channel PCM + Surround EX Six-Channel PCM + EX Six-Channel PCM Dolby SR Two-track printmaster Dolby SR (Six-Ch In) Dolby SR Two-track printmaster Dolby SR (NS1)

Five Ch. Screen

5 Ch. Screen + EX

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Dolby® Model CP650 Installation Manual Introduction

1.8 How to Identify Types of Soundtracks

Edge of film Dolby Digital soundtrack Analog soundtrack Picture area

Figure 1–2 Photograph of Film Soundtracks

A Dolby Digital, Dolby Digital Surround EX, stereo optical (Dolby A-type or SR), or mono optical print should be identified as such on both the film can and the leader. However, with handling, the identification may be lost. If neither is available, close inspection of the film itself will help distinguish the various types. Digital data blocks are printed between the perforations on the side of the film next to the analog (Dolby SR) track.

Dolby Digital or Dolby Digital Surround EX Print

The digital data is clearly visible between perforations next to the analog track. The analo g t rack is Dolby SR encoded.

Analog Dolby SR or A-type Print Analog Mono Print

Clear differences between the stereo channels will be seen in some places along the track.

Both tracks are the same.

Figure 1–3 Film Soundtrack Identification

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Dolby® Model CP650 Installation Manual Introduction

1.9 Regulatory Notices

1.9.1 FCC

This equipment has been tested and found to comply with the limits for a Class F digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with this instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his or her own expense.

1.9.2 Canada

This Class A digital apparatus complies with Canadian ICES-003.

1.9.3 UL

WARNING: Troubleshooting must be performed by a trained technician. Do not attempt to service this equipment unless you are qualified to do so. Check that the correct fuses have been installed. To reduce the risk of fire, replace only with fuses of the same type and rating.

Exposed portions of the power supply assembly are electrically “hot.” In order to reduce the risk of electrical shock, the power cord must be disconnected when the power supply assembly is removed.

The ground terminal of the power plug is connected directly to the chassis of the unit. For continued protection against electric shock, a correctly wired and grounded (earthed) three-pin power outlet must be used. Do not use a groundlifting adapter and never cut the ground pin on the threeprong plug.

1.9.4 UK

The power cord supplied for use in Europe (Dolby Part No. 92021) is not suitable for use in the UK. To use the cord in the UK cut off the CEE7/7 plug and replace with an approved BS 1363 13 A p lug:

• The core that is coloured green and yellow must be connected to the terminal in the plug identified

by the letter E or by the earth symbol

• The core that is coloured blue must be connected to the terminal that is marked with the letter N or

coloured black.

• The core that is coloured brown must be connected to the terminal that is marked with the letter L

or coloured red.

This apparatus must be earthed.

or coloured green or green and yellow.

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Dolby® Model CP650 Installation Manual Introduction

1.9.5 Notices for Europe

This equipment complies with the EMC requirements of EN55103-1 and EN55103-2 when operated in an E2 environment in accordance with this manual.

IMPORTANT SAFETY NOTICE

This unit complies with the safety standard EN60065. The unit shall n o t be exposed to dripp ing or splashing and n o objects filled wi th liquids, such as coffee cups, shall be placed on the equ ipment. To ensure safe operati on and to guard against potential shock hazard or risk of fire, the following must be observed: o Ensure that your mains supply is in the correct range for the input power requirement of the unit. o Ensure fuses fitted are the correct rating and type as marked on the unit. o The unit must be earthed by connecting to a correctly wired and earthed power outlet. o The power cord supplied with this unit must be wired as follows:

Ce materiel est conforme à la norme EN60065. Ne pas exposer cet appareil aux éc laboussures ou aux gouttes de liquide. Ne pa s poser d'objets remplis de liquide, tels que des tasses de café, sur l'appareil. Pour vous assurer d'un fonctionnement sans danger et de prévenir tout choc électrique ou tout r isque d'incendie, veillez à observer les recomm andations su ivantes. o Le selecteur de tension doit être placé sur la valeur correspondante à votre alimentation réseau. o Les fusibles doivent correspondre à la valeur indiquée sur le materiel. o Le m ateriel doit être correctement relié à la terre. o Le cordon secteur livré avec le materiel doit être cablé de la manière suivante:

Dieses Gerät entspricht der Sicherh eitsnorm EN60065. Da s Gerät darf nicht mit Flüss igkeiten (Spritzwas ser usw.) in Berührung kommen; stell e n Sie keine Gefäße, z.B. Kaffeetassen, auf das Gerät. Für das sichere Funktionieren des Gerätes und zur Unfallverhütung (elektrischer Schlag, Feuer) sind die folgenden Regeln unbedingt einzuhalten: o Der Spannungswähler muß auf Ihre Netzspannung eingestellt sein. o Die Sicherungen müssen in Typ und Stromwert mit den Angaben auf dem Gerät übereinstimmen. o Die Erdung des Gerätes muß über eine geerdete Steckdose gewährleistet sein. o Das mitgelieferte Netzkabel muß wie folgt verdrahtet werden:

Questa apparecchiatura è stat a costruita in acc ordo alle norme di sicurezza EN60065. Il pr odotto non deve essere sottoposto a schizzi, spr uzzi e gocciolamenti, e nessun tipo d i oggetto riempito con liquidi, come ad esempio tazze d i caffè, deve essere appoggiato su l dispositivo. Per una perfetta sicurezza ed al fine di evitare eventuali rischi di scossa êlettr ica o d'incendio vanno osservate le seguenti mi sure di sicur ezza: o Assicurarsi che il selettore di cambio tensione sia posizionato sul valore corr etto. o Assicurarsi che la portata ed il tipo di fusibili siano quelli prescritti dalla casa costruttrice. o L'apparecchiatura deve avere un collegamento di messa a terra ben eseguito; anche la connessione rete deve avere un collegamento a terra. o Il cavo di alimentazione a corredo dell'apparecchiatura deve essere collegato come segue:

Esta unidad cumple con la norma de seguridad EN60065. La unidad no debe ser expuesta a goteos o salpicaduras y no deben colocarse sobre el equipo recipientes con liquidos , como tazas de cafe. P ara asegurarse un funcionamiento seguro y prevenir cualquier posible peligro de des carga o riesgo de incendio, se han de observar las s iguientes precau ciones: o Asegúrese que el selector de tensión esté ajustado a la tensión correcta para su alimentación. o Asegúrese que los fusibles colocados son del tipo y valor correctos, tal como se marca en la unidad. o La unidad debe ser puesta a tierra, conectándola a un conector de red correctamente cableado y puesto a tierra. o El cable de red suministrado con esta unidad, debe ser cableado como sigue:

Denna enhet uppfyller säkerhetsstandard EN60065. Enheten får ej utsättas för yttre åverkan samt föremål innehållande vätska, såsom kaffemuggar, får ej placeras på utrustningen." För att garantera säkerheten och gardera mot eventuell elchock eller brandrisk, måste följande observeras: o Kontrollera att spänningsväljaren är inställd på korrekt nätspänning. o Konrollera att säkringarna är av rätt typ och för rätt strömstyrka så som anvisningarna på enheten föreskriver. o E nheten måste vara jordad genom anslutning till ett korrekt kopplat och jordat el-uttag. o El-sladden som medföljer denna enhet måste kopplas enligt foljande:

Deze unit voldoet aan de EN60065 veiligheids-standaards. Dit apparaat mag niet worden blootgesteld aan vocht. Vanwege het risico da t er druppels in het apparaat vallen, dient u er geen vloeistoffen in bekers op te plaatsen. Voor een veilig gebruik en om het gevaar van electrische schokken en het risico van brand te vermijden, dienen de volgende regels in acht te worden genomen: o Controleer of de spanningscaroussel op het juiste Voltage staat. o Gebruik alleen zekeringen van de aangegeven typen en waarden. o Aansluiting van de unit alleen aan een geaarde wandcontactdoos. o De netkabel die met de unit wordt geleverd , moet als volgt worden aangesloten:

Live—Brown Neutral—Blue Earth—Green/Yellow

IMPORTANT – NOTE DE SECURITE

Phase—Brun Neutre—Bleu Terre—Vert/Jaune

WICHTIGER SICHERHEITSHINWEIS

Phase—braun Nulleiter—blau Erde—grün/gelb

NORME DI SICUREZZA – IMPORTANTE

Filo tensione—Marrone Neutro—Blu Massa—Verde/Giallo

AVISO IMPORTANTE DE SEGURIDAD

Vivo—Marrón Neutro—Azul Tierra—Verde/Amarillo

VIKTIGA SÄKERHETSÅTGÄRDER!

Fas—Brun Neutral—Blå Jord—Grön/Gul

BELANGRIJK VEILIGHEIDS-VOORSCHRIFT:

Fase—Bruin Nul—Blauw Aarde—Groen/Geel

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Dolby® Model CP650 Installation Manual

Chapter 2

Installation

Do not connect the CP650 to mains power until all other connections have been made.

If air-conditioning noise is audible in the theatre, arrange for lubrication of the motor and fan bearings, adjustment of belts and drives, and cleaning of filters to reduce the ambient noise to a minimum. If the air-conditioning cannot be repaired, switch it off while the CP650 is being aligned.

2.1 Replacing an Existing Sound System

If the CP650 replaces an existing cinema sound system, play a typical film before you remove the old system so you will have a benchmark for comparison to the new system.

2.1.1 Before Playing the Film:

•

Verify that the existing power amplifiers are in good working order.

• Verify that the existing speakers are in good working order, and that there are no

loose or missing pieces, structural parts, or damaged drivers in the enclosures.

• Verify that all wiring is present and properly connected, and that crossovers are

operating and are correctly adjusted.

• Check the polarity of the speaker connections.

• Verify that there are adequate ground (earth) connections.

• Verify that radio interference problems are adequately resolved.

2.1.2 While Playing the Film:

While running the film, listen carefully in various parts of the theatre for audio system problems, including:

• Hum

• Noise, clicks, or pops

• Distorted sound

• Poor tonal balance (lack of high-frequency or bass content)

These problems must be resolved before the installation process can proceed.

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Dolby® Model CP650 Installation Manual Installation

2.1.3 Disconnect the Old System

• Disconnect power from the existing cinema sound equipment.

• Disconnect all cabling from the existing sound processor. Leave the cables

connected to the power amplifiers, booth monitor, etc.

2.2 Check Fuse and Bypass Mains Voltage Selector

WARNING: Check that the correct main fuse has been installed. To reduce the risk of fire, replace only with fuses of the same type and rating.

The CP650 uses a universal switching power supply that can accommodate nominal mains voltages from 100 to 120, and 200 to 240 VAC, at frequencies from 50 to 60 Hz.

Check Main Fuse

The main power supply fuse is a 6.3 A, 250V, 20 mm, time-lag, low breaking capacity fuse (T 6.3 L). With a small flat-blade screwdriver, open the fuse compartment door on the AC power input housing (See Figure 2–1.)

Figure 2–1 Main Fuse Assembly

Remove the fuse carrier and check that the fuse in the active (left position) is of the correct rating. The fuse carrier must be inserted into the compartment with the fuse oriented to the left. Do not force the carrier into the compartment. Damage will result. The polarizing clip must be attached on the right side of the carrier at the rear. Snap the fuse compartment door closed.

Check Bypass Supply Mains Voltage Setting

The bypass power supply mains voltage selector switch is accessible through a hole in the top cover of the CP650. Use a screwdriver to set the switch to either 120 or 220 VAC Figure2_8 shows the switch location.

Caution: Be sure to check this setting. If the bypass voltage selector is set to 120 V but the unit is connected to 220 V mains voltage, the bypass power supply fuse will blow.

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Dolby® Model CP650 Installation Manual Installation

Bypass Power Supply Fuse

The bypass power supply fuse is accessible by removing the plastic front-panel and the front subpanel. It is located above the power/bypass switch. The fuse values are:

For 110 VAC Mains T 200 mA L (time-lag, 200 mA, 20 mm, low breaking capacity, 250 V)

For 220 VAC Mains T 100 mA L (time-lag, 100 mA, 20 mm, low breaking capacity, 250 V)

Caution: Early CP650s used a 315 mA fuse for all mains voltages. The fuse ratings above should be used for more reliable overcurrent protection.

Internal Fuse

The switching DC power supply contains a separate internal fuse, not accessible to the installation engineer or user. Do not remove the power supply cover. The CP650 main fuse will protect most fault conditions. If this fuse blows, the power supply has certainly failed.

2.3 Mount the CP650

To avoid heat or hum pickup problems, do not mount the Dolby CP650® immediately above or below the power amplifiers. Locate the power amplifiers away from the CP650 to avoid hum pickup problems. Always leave a 1U space (43 mm, or 1.75 inches) above and below the CP650 to provide adequate ventilation. Install an air guide or baffle to deflect hot air from equipment below the CP650.

To ensure good ground contact, install a star washer on at least one (and preferably all) rack-mounting screw(s) per piece of equipment (Figure 2–2). This will also aid in the prevention of electrical noise problems.

Figure 2–2 Star Washers and Rack-Mounting Screws

Proper shielding and termination of cables and cable assemblies are also very important. Follow the methods shown in the wiring diagrams.

If you are installing a Dolby Cat. No. 701 Digital Soundtrack Reader, refer to its installation manual for mounting and alignment.

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Dolby® Model CP650 Installation Manual Installation

2.4 Mount the Auditorium Assist Microphone

Auditorium AssistTM operation requires the use of the Cat. No. 735 microphone. Mount the microphone permanently in the auditorium, at a convenient location away from sound sources. If the rear wall is used, the microphone should be centered between surround speakers. Wall plates with an integrated XLR connector are available. Examples include:

Switchcraft J3FS—Stainless Steel Whirlwind WP1B/1FND—Black

Connect the microphone to the mic input located on the rear panel of the CP650 cinema processor. If the microphone input in your installation is currently dedicated to other uses, such as an emergency public address, install the necessary hardware to switch between microphones.

2.5 Connect the CP650

Refer to the appropriate foldout pages, located at the end of this chapter, showing connections to the CP650.

Shields must be connected as shown in the foldout pages to avoid radio frequency interference.

Note: Follow all local codes and regulations covering electrical wiring. It is recommended that conduit be used for wiring runs.

Connector shells have been included in your installation kit for use in countries that are governed by the EMC directives. The shells must be used as noted on the foldout pages.

2.5.1 Motor-Start Relays (Models CP650 and CP650D)

For two-projector installations, motor-start relays are required for projector changeover. Digital data on the soundtrack is read in advance of the picture; therefore an advanced changeover signal is required. Projector motor-start contact closures provide this signal to the CP650. Isolated contact closures from mechanical or opto- isolated relays wired across projector motors must be used. Refer to the Installation

Wiring Inputs and Control diagram at the end of this chapter. Signal levels:

Motor Start: Less than 1 VDC with respect to signal ground Motor Off: Greater than 3.5 VDC, less than 18 VDC

If the CP650 is to be used in a platter operation (single projector), a jumper must be installed. A pre-wired connector is installed at the factory for this purpose.

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Dolby® Model CP650 Installation Manual Installation

2.5.2 Remote Controls

Three types of remote controls can be used with the CP650. A maximum of three remote units (in any combination) can be used.

The Cat. No. 779 CP650 Remote Control Unit duplicates the front-panel format selection, fader, and mute functions of the CP650.

The Cat. No. 771 Remote Fader Unit duplicates the front-panel main fader knob and level display of the CP650.

A customer-supplied 100 kȍ linear pot, wired as a variable resistor, can also be used. Minimum pot resistance corresponds to a front-panel fader setting of maximum (10).

Details on how to connect any of these remote controls to the CP650 are shown in Chapter 8.1 and in the Installation Wiring Input and Control drawing located at the end of this chapter.

2.5.3 Solar Cell Reader Boards

Most new projectors sold around the world incorporate a reverse-scan LED analog soundhead reader. In addition, many existing projectors are being upgraded to include this superior method of playing back SVA soundtracks. The Dolby Cat. No. 655 solar cell preamp board is an example of this kind of upgrade. The output of the solar cell in this system is at a lower level than a normal incandescent exciter lamp solar cell. In order to provide the correct signal level for the cinema processor, this small preamp board is mounted in the soundhead. Some care needs to be given to the wiring between the board and the CP650 in order to avoid grounding problems and to provide immunity to RF interference. In principle, this means separating the audio ground connections and the RF shielding screen connections.

The 0 V point (audio ground) must be connected from the inboard reader board to the CP650 by a separate wire (or wires) along with the audio signal wires. The cable shield (screen) must be kept separate from the audio ground connections. It must be connected only to the chassis or enclosure of the equipment at each end.

The following diagrams show two connectors on the Cat. No. 655 circuit board. The three-pin connector, J1, is used for the power connections. The signal output connector, J2, provides six output pins: two each for the balanced left and right outputs, and two 0 V audio ground connections.

The physical orientation of the board mounting in the projector and the orientation of the connector body mounting on the board affect which channel appears on which pin of the connector. Be aware that pin allocations for the channels will vary depending on mounting arrangements of the board and connector. The J2 connector pin solder hole with a square outline is pin 1.

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Dolby® Model CP650 Installation Manual Installation

Table 2–1 Solar Cell Preamp Board Connectors

J2 Pin Number Signal

1 Right (or Left) + 2 Signal Ground 3

Right (or Left) –

4 Left (or Right) + 5 Signal Ground 6 Left (or Right) –

J1 Pin Number Power from CP650

7 +15 V 8 –15 V 9 Signal Ground

There must be a connection between the ground pins at the Cat. No. 655 solar cell circuit board and the audio common in the CP650. This connection must not use the shield of the optical input cable, since doing so may impose RF energy on the CP650 ground system.

Pin numbers 6 and 9 of each 9-pin D-connector (“Projector”) on the CP650 allow these connections to be made. The wire that connects either of these pins to the Cat. No. 655 audio ground should pass inside the same shield as the optical input cables and not connect with the shield at any point.

–

Gnd

–

Gnd

Cat.No.655 Wiring Diagram

Ground wire on pin 5, OPTIONAL Ground wire on pin 2, REQUIRED

Gnd

+Vdd

–

Vdd

Out 1+

Out 1–

Out 2+

Out 2–

Shield

CP650

Optical In

Figure 2–3 Cell Preamp Wiring Using Two 3-Conductor Shielded (Screened) Cables

–

Gnd

–

Gnd

Cat.No.655 Wiring Diagram

Ground wire on pin 5, OPTIONAL Ground wire on pin 2, REQUIRED

Gnd

+Vdd

–

Vdd

Out 1+

Out 1–

Out 2+

Out 2–

Shield

CP650

Optical In

Figure 2–4 Cell Preamp Wiring Using One 5- or 6-Conductor Shielded (Screened) Cable

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Dolby® Model CP650 Installation Manual Installation

For Non-EU Countries Only:

If it is necessary to use two- or four-conductor shielded cables, use the following wiring diagrams.

+Vdd

–

Vdd

Out 1+

Out 1–

Out 2+

Out 2–

Belden 8451 or equivalent

Shield

CP650

Optical In

J1 1

Shield

–

Gnd

–

Gnd

Cat.No.655 Wiring Diagram

Ground wire on pin 5, OPTIONAL Ground wire on pin 2, REQUIRED

Gnd

Figure 2–5 Cell Preamp Wiring Using Two 2-Conductor Shielded (Screened) Cable

+Vdd

–

Vdd

Out 1+

Out 1–

Out 2+

Out 2–

Belden 8723 or equivalent

Shield

CP650

Optical In

Shield

–

Gnd

–

Gnd

Figure 2–6 Cell Preamp Wiring Using One 4-Conductor Shielded (Screened) Cable

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Dolby® Model CP650 Installation Manual Installation

2.5.4 Analog Nonsync Sources

The CP650 has two sets of analog nonsync inputs, designated nonsync 1 (Format 60), and nonsync 2 (Format 61). The input impedance is 11 kΩ. They both have a wide

range of input level adjustment, but to further extend the possible range of input levels, the two sets of inputs have different gain adjustment ranges:

• The nonsync 1 input will accommodate input levels between approximately

0.2 and 4 V.

• The nonsync 2 input will accommodate input levels between approximately

0.06 and 1.5 V.

2.5.5 Digital Audio Sources

The CP650 can accept AES/EBU or S/PDIF digital audio bitstreams, generated by digital audio sources including CD players, DAT recorders, DVD players, satellite television receivers, HDTV receivers, or HD video players.

With the Cat. No. 790 board (included with the standard model CP650) installed, the CP650 accepts up to four two-channel PCM (pulse code modulated) bitstreams. Each bitstream contains the data for two channels of PCM audio. Sampling rates of up to 48 kHz—with up to 24-bit resolution—are accommodated. This bitstream format can be found on the digital output connector of a CD player, DAT recorder, DVD player, or any basic piece of digital audio equipment. The inputs are S/PDIF single-ended signals. To use these inputs, a digital input format (Format 80, 81, 88, 89, or 90) may be assigned to one of the user-definable format buttons U1, U2, or NS. See Sections 7.8 and 7.9.

With the Cat. No. 794 board (included with earlier CP650s) installed, the CP650 accepts a digital audio bitstream. The Cat. No. 794 can accept either AES/EBU differential signals or S/PDIF single-ended signals, depending on jumper settings on the board itself (see Figure 2-7). To use this input, Format 80 (Master Digital In) must be assigned to one of the user-defined format buttons U1, U2, or NS. See Sections 7.8 and 7.9.

With an optional Cat. No. 778 board installed, the CP650 gains the capability to accept up to four two-channel digital audio bitstreams, and provides up to five digital two-channel audio bitstream outputs. The CP650 can accept either PCM or Dolby Digital bitstreams on its AES1 digital audio input. Additionally, the Cat. No. 778 allows the CP650 to accept up to four PCM-formatted AES/EBU inputs, giving a total of eight discrete audio channels. The board provides five AES/EBU outputs to support up to ten discrete audio channels. All inputs and outputs comply with AES/EBU standards. The CP650’s main analog outputs are disabled with a Cat. No. 778 installed.

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Dolby® Model CP650 Installation Manual Installation

Connecting to the Digital Audio Input

The external electrical connections to the optional boards in the CP650 are available on the 25-pin D-connector marked “Option I/O” on the rear panel of the CP650. Since the boards have different functionality, each pin on this connector changes its function depending on which optional card is installed. Refer to Table B-2 for the signal definitions. Make external connections by soldering the appropriate wires to the male solder-cup connector shipped with the CP650, then plug this connector into the Option I/O connector on the CP650.

Note: When wiring to the digital inputs on the Cat. No. 790 or Cat. No. 778, be sure to ground all unused digital inputs. Failure to do so will cause unused channels to show signal level due to crosstalk between the used digital inputs and the unused digital inputs.

In a CP650 equipped with a Cat. No. 790 board, the input type is S/PDIF. See Figure 2-7 for Option I/O connector hookup details. Refer to Table B-2 for signal definitions.

OPTION CARD I/O

S/PDIF Digital Inputs

7 2

25 21

Figure 2–7 Cat. No. 790 S/PDIF Connections

In a CP650 equipped with the earlier Cat. No. 794 board, the input type (AES/EBU or S/PDIF) must be selected using jumpers on the board. The default factory setting is AES/EBU. See Figure 2-7 for Option I/O connector hookup details. Refer to Table B-2 for signal definitions. When a Cat. No. 778 board is installed, the input type is always AES/EBU.

black

MADE IN U.S.A/U.K.

AES/EBU

S/PDIF

red

For Cat. No. 778

112

For Cat. No. 794

black red

AES/EBU

Digital Output Source

332

MADE IN U.S.A/U.K.

AES/EBU

S/PDIF

Digital Output Source

Figure 2–8 Cat. Nos. 794/778 AES/EBU and S/PDIF Jumper Selections and Connections

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Dolby® Model CP650 Installation Manual Installation

Professional Interface Standards for Digital Audio

There are two professional interface formats used for digital audio: AES/EBU (also known as AES3) and AES3id. These stream the same digital data and professional

audio header information over copper conductor links, but use different types of conductors and connectors.

AES/EBU uses a balanced connection (two conductors plus shield) with a characteristic input impedance of 110Ω, nominal peak-to-peak signal level of 5 V, and most commonly, XLR connectors. The typical maximum transmission distance is 100 meters. AES3id uses an unbalanced connection (one signal conductor plus shield) with a characteristic input impedance of 75Ω, peak-to-peak signal level of 1 V, and

BNC (“push and twist”) connectors. The typical maximum transmission distance is 1000 meters.

Professional digital audio equipment usually uses the AES/EBU format because balanced operation yields superior noise immunity, as it does with analog audio signals, and because XLR connectors have been standard on analog professional audio equipment.

Professional video equipment usually uses the AES3 variation of this interface, with BNC connectors. Like the use of XLR connectors on pro audio equipment, the adoption of BNC connectors for the audio on professional video equipment stems from their existing use for the video signal. Also, the unbalanced AES3 signal can connect to more than one piece of equipment by using the loop-through connectors that are available on some devices, and is robust for long cable runs.

Consumer Interface Standards for Digital Audio

The consumer interface standard for digital audio is S/PDIF (IEC61937). S/PDIF is found using either coaxial unbalanced connections (one signal conductor plus shield) with a characteristic input impedance of 75Ω with RCA (phono) connectors, or a fiber-optic cable with ToslinkTM connectors. The unbalanced coaxial connection has a peak-to-peak signal level of 0.5 V. The typical maximum transmission distance is 10 meters. Although S/PDIF-specific cables with suitable connectors can be purchased, good results can also be obtained using high-quality 75Ω video cable with the appropriate connectors and/or adapters.

Cable Issues

Even in digital audio, noise-free signals are still very important. The cable used for digital signals is specifically designed for digital audio use, even though it appears to be the same as that used for analog audio or video signals. Any professional audio equipment or broadcast supply company can provide 110Ω cable with connectors (or without, if you wish to terminate them yourself) for AES/EBU connections, and highquality 75Ω video cables with BNC connectors for AES3id connections. Use of cables or connectors with incorrect impedance or not designed for digital transmission compromises the integrity of the bitstream and may create an unreliable link between pieces of equipment, particularly with long cable runs.

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Multiple Sources: Conversion Between Interface Standards

Although some details of the bitstreams used in the AES and S/PDIF standards are different, the audio information is exactly the same. As a consequence, most audio equipment will accept either standard with no need to convert the bitstream itself; this is the case with the CP650. However, if you intend to connect sources across different types of digital audio inputs, Do not attempt to convert a digital interface type by, for example, directly wiring an XLR connector to a BNC or RCA plug. This causes an impedance mismatch and signal reflections, resulting in degradation of the digital waveform. It may seem to work, but the results are unreliable and dropouts occur.

For conversion between the AES3id and S/PDIF formats you can use high-quality RCA (phono plug)-to-BNC adapters because the cable and impedance are both the same (75Ω).

For conversion between the AES/EBU and AES3id or AES/EBU and S/PDIF formats, a simple and economical method is to use inline transformers. These devices perform the necessary impedance and balanced/unbalanced conversion. Table 2–2 shows some examples of suitable adapters. The unbalanced connector in these examples is a BNC. BNC-to-RCA adapters can be added to connect to consumer S/PDIF connections. The units listed use passive circuitry.

Table 2–2 Examples of Available Balanced ↔ Unbalanced Adapters

Adapter Type Neutrik® CanareTM

XLR female 110Ω in to BNC Female 75Ω out BNC Female 75Ω in to male XLR 110Ω out

NA-BF BCJ-XJ-TRA

NA-BM BCJ-XP-TRA

Higher-priced units incorporating active circuitry are also available. These offer additional features like multiple inputs, inputs for Toslink digital connections, and multiple outputs.

2-11

Page 36

Dolby® Model CP650 Installation Manual Installation

2.6 Exploded View and Board Locations

Dolby Digital Surround EX

Decoder / Digital Aux. Input Card

Dolby Digital Surround EX Decoder / Digital I/O Card

Analog I/O and Bypass

Front Sub-Panel

Mounting Screws (7)

Cat. No. 790

Cat. No. 778

Cat. No. 774A

System Controller

Cat. No. 772A

-or-

Front Panel Mounting Screw

Cat. No. 791 Digital Crossover Card (for use with Cat. No. 790 only)

Cat. No. 773 Dolby Digital Decoder

Power / Bypass Button

Bypass Mains Voltage Selector Switch (110/220 VAC)

Cat. No. 792 Bypass Power Regulator

Bypass Power Supply Fuse Holder 5 X 20 MM 110 VAC: T 200 mA L 220 VAC: T 100 mA L

Cat. No. 776 Power Supply Assembly

Figure 2–8 Model CP650 Exploded View

Disassembly steps can be found in the troubleshooting section of this manual. (See Section 9.3.2.)

2-12

Page 37

Dolby® Model CP650 Installation Manual

Projector 1

Cat. No. 701

Digital Reader

Inboard Digital

Basement Reader

Projector 2

Cable Part Numbers: 83141 (30 feet) (9.1 meters) 83237 (50 feet) (16.2 meters)

+15V 100 mA MAX

To Automation

(See Interface Requirements

in Appendix B)

100 - 240 Vac 50 - 60 Hz 120 W

CAUTION

Toreduce therisk offire

replace only with same

250V time-lag fuse.

FUSE T 6.3A L

5mmx20mm

type and rating

SHIELD

GROUND

MUTE

NONSYNC

CUS

LISTED

PROFESSIONALAUDIO EQUIPMENT 4J06

11 10 05 04 01

Cat. No 771

Terminals

DATA

GND

Notes:

Follow all local electrical and building codes.

Use grounded (earthed) conduit wherever possible. Avoid routing signal wiring near electric motors, rectifiers, power wiring, dimmer wiring, or other sources of electrical noise.

For two conductor with shield wiring, use Belden 8451 2-conductor shielded cable or equivalent: tinned copper, twisted pair, 22 AWG stranded tinned copper drain wire, aluminum-polyester shield, 100% shield coverage, conductor-to-conductor 111 pF per meter.

MUTE

NONSYNC

11 10

REMOTES AND AUD. FADER

REMOTE

FADER

This device complieswith Part 15 of the FCCRules. Operation is subjectto the following two conditions: (1)this device may notcause harmful interference, and (2) this device must acceptany interference received, including interference that maycause undesired operation.

This ClassA digital apparatuscomplies with Canadian ICES003.

Remote Fader

Cat. No 771

7.0

DATA

GND

Projector 1

Projector Changeover Relays, Pulsed Contacts

Open

Closed

50 ms

minimum

Projector 2

Projector Changeover Relay

Maintained Closed Contact

Selects Projector 2

For Dolby Digital Installations

Proj 1 Motor Start Relay

Projector Motor

Proj 2 Motor Start Relay

Projector Motor

AUTOMATION

DATA

N/C

H/I OUTPUT

132546

San Francisco U.S.

READER 1

01 04 05

READER 2

L L+ C C R R+ Ls Ls + Rs Rs + SW SW +

17 20 23 24 25

MAIN AUDIO OUTPUT

DATA

GND

Auditorium Fader (100K Linear Pot)

Remote Control Unit

Cat. No. 779

7.0

Digital Cinema Processor

Wootton Bassett U.K.

Dolby Digital

NONSYNC IN 1

NONSYNC IN 2

Front View of Pot

SERIAL DATA

CP650

MOTOR START

WARNING

Risk of electric shock.

Do not open.

No user serviceable parts

inside. Refer all service

to qualified personnel.

This equipment must be

earthed/grounded.

6-CH AUDIO INPUT

(External Digital Processor)

Cat. No. 779

Terminals

DATA GND

Set address switch prior to use.

MS1 P1 P1/ P2 P2 MS2

For three conductor with shield wiring, use Belden 8771 3-conductor shielded cable or equivalent: tinned copper, twisted pair, 22 AWG stranded tinned copper drain wire, aluminum-polyester shield, 100% shield coverage, conductor-to-conductor 75 pF per meter.

All shields must be connected to the CHASSIS of the CP650. This achieves the required RF interference immunity. A metal housing must be used for all D-connectors and the shields must be connected to the housing. Chassis ground and circuit (audio) ground are internally connected.

(RS-232)

ETHERNET

OPTION CARD I/O

SWITCH SIDE VIEW

See manual.

For future

Automation use

MIC. INPUT

OPTICAL IN 1

R R

L L

OPTICAL IN 2

Single Projector2-Projector Changeover

Jumper Plug

(shipped installed on unit)

All shields must be connected to the metal shield of the D-connector.

FB425A04.CDR

CD, Tape, etc.

Non-Sync 2

Non-Sync 1

5 4 23 1

9 786

Projector 1

Projector 2

43 12

AUDITORIUM ASSIST

PA Microphone 1

(Or Mic-multiplexer

red

black

red

black

OR:

red

black

red

black

6987

Microphone

for setup)

The physical board mounting in the projector and the connector affect which channel appears on which pin of the connector.

that pin allocations for the channels will vary depending on mounting arrangements of the board and connector

solder hole with a square outline is pin 1.

15 V phantom power switchable via front setup control panel dip switch number 3.

172

Reverse Scan / LED

Analog Reader Board

132465321

OUT 1 +

OUT 1 OUT 2 +

OUT 2 -

orientation

. The J2 connector pin

red black

Digital Output Source

AUD. ASSIST

User supplied

Switch Box (Optional)

S/PDIF

Be aware

Solar Cell

green

black

red

SHIELD L Rs Ls R C SW

6-Channel Analog Input

(all unlabeled pins are signal ground)

(normal operating level = 300 mV)

CP650 INSTALLATION WIRING

INPUT AND CONTROL CONNECTIONS

2-13

Page 38

Dolby® Model CP650 Installation Manual Installation

Hearing

Impaired

System

Screen Speakers

Surround Speakers

(without Dolby Digital

Surround EX )

For unbalanced input amplifier

one channel shown

Signal

Gnd

red black

black

red

black

red

black

red

black

red

black

red

L+C+R

red

blk

100 - 240 Vac 50 - 60Hz 120 W

CAUTION

Toreduce therisk offire

replace only with same

type and rating

250V time-lag fuse.

FUSE T 6.3A L

5mmx20mm

CUS

LISTED

PROFESSIONALAUDIO EQUIPMENT 4J06

MUTE

NONSYNC

U1 11 10

REMOTES AND AUD. FADER

REMOTE

DATA

FADER

N/C

H/I OUTPUT

This ClassA digital apparatuscomplies with Canadian ICES003.

1 1

black

red

black

red

black

red

black

red

AUTOMATION

MAIN AUDIO OUTPUT

San Francisco U.S.

01 04 05

Digital Cinema Processor

READER 1

READER 2

L L+ C C

+ R R+ Ls Ls + Rs Rs + SW SW +

17 20 23 24 25

13 13

25 25

CP650

Wootton Bassett U.K.

SERIAL DATA

(RS-232)

ETHERNET

MIC. INPUT

MOTOR START

Dolby Digital

NONSYNC IN 1

NONSYNC IN 2

6-CH AUDIO INPUT

(External Digital Processor)

No user serviceable parts

inside. Refer all service

This equipment must be

MS1 P1 P1/ P2 P2 MS2

WARNING

Risk of electric shock.

Do not open.

to qualified personnel.

earthed/grounded.

OPTION CARD I/O

OPTICAL IN 1

R R

OPTICAL IN 2

L L

CP650 with Cat.No.790 / 791 (Dolby Digital Surround EX option)

Model CP650D requires optional UEX/650 upgrade kit.

Model CP650SR requires optional UEX/650 and

Included with Model CP650.

(see input and control diagram)

black

red

black

red

black

red

black

red

black

red

FB425B04.CDR

UD/650 upgrade kits.

AES/EBU inputs

Signal

Gnd

Signal

Gnd

Signal

Gnd

Signal

Gnd

Back Surround Left

Back Surround Right

Left Surround

Right Surround

Gnd

black

red

black

red

Signal

Subwoofer

Notes:

Follow all local electrical and building codes.

Use grounded (earthed) conduit wherever possible. Avoid routing signal wiring near electric motors, rectifiers, power wiring, dimmer wiring, or other sources of electrical noise.

2-14

black

red

black

red

black

For unbalanced input amplifier

one channel shown

Signal

red

Gnd

black

CP650 INSTALLATION WIRING

AUDIO OUTPUT CONNECTIONS

Page 39

Dolby® Model CP650 Installation Manual Installation

Hearing

Impaired

System

Screen Speakers

Do not open.

(RS-232)

ETHERNET

MS1

OPTION CARD I/O

P1 P1/ P2 P2 MS2

MIC. INPUT

OPTICAL IN 1

R R

L L

OPTICAL IN 2

FB425J04.CDR

black

red

L+C+R

100 - 240 Vac 50 - 60 Hz 120W

CAUTION

Toreduce therisk offire

replace only with same

type and rating

250V time-lag fuse.

FUSE T 6.3A L

5mmx20mm

CUS

LISTED

PROFESSIONALAUDIO EQUIPMENT 4J06

AUTOMATION

MUTE

NONSYNC

U1 11 10

REMOTES AND AUD. FADER

REMOTE

DATA

FADER

N/C

H/I OUTPUT

This ClassA digital apparatuscomplies with Canadian ICES003.

San Francisco U.S.

READER 1

01 04 05

READER 2

17 20 23 24 25

MAIN AUDIO OUTPUT

Digital Cinema Processor

Wootton Bassett U.K.

Dolby Digital

L L+ C C R R+ Ls Ls + Rs Rs + SW SW +

NONSYNC IN 1

NONSYNC IN 2

SERIAL DATA

CP650

MOTOR START

WARNING

Risk of electric shock.

No user serviceable parts

inside. Refer all service

to qualified personnel.

This equipment must be

earthed/grounded.

6-CH AUDIO INPUT

(External Digital Processor)

CP650 with Cat.No.790 / 791

1 1

L (low)

black

Signal

Gnd

red

black

red

black

red

13 13

25 25

black

red

C (low)

black

Signal

Gnd

red

black

red

Surround Speakers

(without Dolby Digital

Surround EX )

Subwoofer

Signal

Gnd

Signal

Gnd

Signal

Gnd

R (low)

L (high)

C (high)

R (high)

black

red

black

red

black

red

Signal

Gnd

Signal

Gnd

Signal

Gnd

Signal

Gnd

Signal

Gnd

black

red

black

red

black

red

black

red

black

red

black

red

black

red

black

red

black

red

black

red

black

red

black

red

black

red

2-15

CP650 INSTALLATION WIRING

AUDIO OUTPUT CONNECTIONS

FOR BIAMPLIFIED SCREEN SPEAKERS

Page 40

Dolby® Model CP650 Installation Manual Installation

Hearing

Impaired

System

Screen Speakers

Do not open.

(RS-232)

ETHERNET

MS1

OPTION CARD I/O

P1 P1/ P2 P2 MS2

MIC. INPUT

OPTICAL IN 1

R R

OPTICAL IN 2

L L

FB425K04.CDR

black

red

L+C+R

100 - 240 Vac 50 - 60 Hz 120W

CAUTION

Toreduce therisk offire replace only with same

type and rating

250V time-lag fuse.

FUSE T 6.3A L

5mmx20mm

CUS

LISTED

PROFESSIONALAUDIO EQUIPMENT 4J06

AUTOMATION

MUTE

NONSYNC

U1 11 10

REMOTES AND AUD. FADER

REMOTE

DATA

FADER

N/C

H/I OUTPUT

This ClassA digital apparatuscomplies with Canadian ICES003.

San Francisco U.S.

READER 1

01 04 05

READER 2

17 20 23 24 25

MAIN AUDIO OUTPUT

Digital Cinema Processor

Wootton Bassett U.K.

Dolby Digital

L L+ C C R R+ Ls Ls + Rs Rs + SW SW +

NONSYNC IN 1

NONSYNC IN 2

SERIAL DATA

CP650

MOTOR START

WARNING

Risk of electric shock.

No user serviceable parts

inside. Refer all service

to qualified personnel.

This equipment must be

earthed/grounded.

6-CH AUDIO INPUT

(External Digital Processor)

CP650 with Cat.No.790 / 791

1 1

L (low)

Gnd

black red

black

red

Signal

13 13

25 25

L (mid)

Gnd

black red

black

red

Signal

C (low)

Gnd

black red

black

red

Signal

C (mid)

Gnd

black red

black

red

Signal

R (low)

Gnd

black red

black

red

Signal

R (mid)

Gnd

black red

black

red

Signal

L (high)

Gnd

black red

black

red

Signal

C (high)

Gnd

black red

black

red

Signal

R (high)

Gnd

black red

black

red

Signal

Surround Speakers

(without Dolby Digital

Surround EX )

Subwoofer

Signal

Gnd

Signal

Gnd

Signal

Gnd

black

red

black

red

black

red

black

red

black

red

black

red

2-16

CP650 INSTALLATION WIRING

AUDIO OUTPUT CONNECTIONS

FOR TRIAMPLIFIED SCREEN SPEAKERS

Page 41

Output

Bypass

Fader

Bypass

Level

(Trimpot)

(EEPOT)

B-Chain

Audio

Bypass

6-Ch

EPOT Level

Out

Relays

Outputs

Balanced

Control

and Treble

DAC

6-Ch

Bulk EQ

ADC

for

Self-Test

Bit, Word, and Frame Clocks

ESSI

Convertor

Analog Card

for all A/Ds, D/As and the

Sample Rate Converter

Digital Card

Digital Processes

Analog Processes

DSPs

Boot

Status

Configuration

Shaft

Front Panel

20 char

by 4 line

Encoder

Switches

LCD display

CP650 SYSTEM

FLOW CHART

Front panel

Matrix

Decoder

Model CP650 Installation Manual

Noise

EQ and

Slit-Loss

Dolby

Reduction

Digital Card

ADC

2-Ch

with

Optical

Preamp

EEPOTS

Card

Option

for

DAC

Analog Card

Self-Test

Dolby Digital

ADC

6-Ch

Input

Multi-

plexer

Front end

MUX

Controller and System Memory

Rate

6-Ch

Sample

Converter

Load

Dynamic

MUX

From

B-Chain

Option

EQ DSP

Cat.No. 773

Digital Card

Option Card

Remote

Interface

Accessory

Interface

PC Serial

Port

Control

Parallel

Automation

Fader

Auditorium

2-17

2-Ch

Non-

2-Ch

Proj 2

Proj 1

Sync

Non-

Sync

6Ch

Reader

Back

Panel

Connector

FB425F01.CDR

Page 42

Page 43

Dolby® Model CP650 Installation Manual

Chapter 3

Front Panel and Alignment Overview

This chapter describes the features on the CP650 front panel, along with an overview of the general principles involved in the alignment of Dolby useful to develop an understanding of why the CP650 is aligned as described in this manual. If the installer is already familiar with the CP650 and these principles, or is in a hurry to complete the installation, this chapter may be read later. Continue the setup procedure beginning with the next chapter.

3.1 The CP650 Front Panel

Bypass Power Supply Failure Indicator

Indicates a problem is detected in the bypass

Setup Control Panel Access Door

Opens using the tab on the lefthand side. Exposes the setup control panel for use by the service engineer.

in the power supply.

Front Panel Display

Displays processor condition, operation mode, and is used to perform alignment by the service engineer when PC setup software is not used.

Format 10 Dolby Digital

L M1 0

mute

cinema equipment. It is

Projector Signal Indicators

P1 and P2 show which projector’s output is being processed by the CP650.

Level Display

Displays fader setting. Ranges from 0.0 to

10. Normally set to 7.0.

P1 P2

Format Buttons

Used to select the format: 01 Mono 04 Dolby A-Type 05 Dolby SR 10 Dolby Digital 11 External six channel input U1 User-defined during setup

(normally Format 13) U2 User-defined during setup NS Normally Format 60

Nonsync 1,

(can be User-defined)

Next Menu Button

Steps through the menu list.

Select Button

Selects a parameter to change. The change is made by rotating the main fader knob.

OK Button

Used to store the displayed setting in the CP650 memory.

Mute Button

Fades down and fades up the signal to all channels without disturbing the current main fader setting. Flashes red when activated to fade-down.

Main Fader Knob

Controls sound level and is used for menu operations and data selection during setup. The knob rotates continuously with no end-stops.

Figure 3–1 Front-Panel Controls

3-1

Power Supply Button

When this button is illuminated red, the unit is in bypass mode, either because bypass mode has been manually selected (by using the button) or because a fault has been automatically detected. In bypass mode, the unit is powered by the built-in bypass power supply. While the main power supply is in use, this button is not illuminated, and the screen and other indicators operate normally

Page 44

Dolby® Model CP650 Installation Manual Front-Panel and Alignment Overview

Front-Panel Display

L Le C Re R Rs Bsr Bsl Ls SW

Figure 3-2 Front-Panel Display Showing All Possible Channels Active

Day-to-day operation of the CP650 is performed through interaction with this display. The 20-character, four-line LCD provides a read-out of processor condition and operation mode. It can be used by the service engineer to align the CP650 if PC setup software is not used.

Figure 3-2 shows the display that is active when the CP650 is processing and playing a digital signal connected to the CP650 input with all channels active. The top two lines display the current format, which in this case is Dolby

Digital Surround EXTM, with five screen channels active. The bottom left area contains an active bar graph display of the sound signals present on each channel. The bars move, confirming that sound is passing through the CP650.

The bars are displayed starting with the Left screen channel, and moving clockwise around the auditorium:

Left screen, Left Extra screen, Center screen, Right Extra screen, Right screen, Right Surround, Back Surround Right, Back Surround Left, Left Surround, Subwoofer.

The L on the display indicates that fader control is set to local, meaning that the fader knob on the front panel of the CP650 (and any Dolby remote box fader knob) controls the sound level in the auditorium. If the display shows an A, an external non-Dolby auditorium fader knob controls the sound level.

M1 indicates that the projector 1 motor contact is closed or jumpered (motor-start connector on the back panel). The motor running signals are used in the timing of changeovers while running Dolby Digital films in a two-projector system.

The 0 shown on the bottom right is the Dolby Digital film error rate. The first indication of satisfactory digital film playback is the detection of a low error rate. The error rate is a number between 0 and 8. With a correctly aligned digital film reader, most films will play at an error rate of 6 or lower. If the digital error rate exceeds 8, or if the display shows F (data not readable) or “–”(no digital soundtrack), the CP650 automatically switches to playing the film’s analog soundtrack until usable data appears.

3-2

Page 45

Dolby® Model CP650 Installation Manual Front-Panel and Alignment Overview

Other Possible Front-Panel Sound Format Displays

L C R Rs Ls SW

Figure 3-3 Front-Panel Display Showing a Dolby Digital Film Playing

Figure 3-3 shows the display when the CP650 is playing a Dolby Digital soundtrack with no Dolby Digital Surround EX decoder board installed. Since there are no Le, Re, Bsr or Bsl channels present in this configuration, no signal bars are indicated for those channels.

L C R Rs Bsr Bsl Ls SW

Figure 3-4 Front-Panel Display Showing Dolby Digital Surround EX Film Playing

Figure 3-4 shows the display when the CP650 is equipped with a Dolby Digital Surround EX decoder board, and playing a Dolby Digital Surround EX soundtrack. The additional Back Surround Left and Back Surround Right channels are present in this configuration.

The digital sound data from current films produced with the Dolby Digital Surround EX process contains auto-switching bits (Surround EX flags). A CP650 equipped with the Cat. No. 790 Surround EX Board detects these bits and automatically switches the CP650 to Surround EX decoding. If the flags indicate that the film is not a Surround EX film, or if the flag bits are not present, Surround EX mode is switched off. The Bsr and Bsl channels are automatically configured for either 5.1 mode or Surround EX mode.

Front-Panel Sound Format Display on Units with Earlier Software

The bar graph display on CP650s running software earlier than version 2.1.x.x (x can be any number) is slightly different:

Dolby Digital Surround EX board installed: Not installed:

L C R Ls Rs SW Bsl Bsr L C R Ls Rs SW

Figure 3-5 Front-Panel Display When Running Earlier Software

3-3

Page 46

Dolby® Model CP650 Installation Manual Front-Panel and Alignment Overview

Level Display

The main fader level is displayed as a two-digit number. Starting from a display of

0.0, the level increases from –90 to –10 dB (display 4.0) as the fader knob is turned clockwise. The level then increases in smaller steps from –10 to +10 dB (display 10). As with previous generations of Dolby cinema processors, a fader setting of 7.0 (0 dB) is the nominal correct operating level. This setting matches the level used during production of the film.

Main Fader Knob

Use this knob to adjust the sound level. A fader reading of 7.0 is the nominal correct operating level. The main fader knob rotates continuously with no end-stops. The knob is also used for data selection during setup operations.

When the fader knob is rotated between readings 0 and 4.0, the output level changes in 20 dB steps between –90 and –10 dB. When the fader knob is rotated between readings 4.0 and 10, the output level changes in 3 1/3 dB steps between –10 dB and +10 dB.

-10

-20

-30

Output

Level (dB)

-40

-50

-60

-70

-80

-90 10

20 dB

per step

Figure 3–3 Fader Characteristic

Projector Signal Indicators

3 1/3 db per step

32 45678

Fader Level

P1 and P2 show which projector optical input has been selected.

Bypass Power Supply Failure Indicator

This indicator lights if a problem is detected in the bypass power supply circuitry.

3-4

Page 47

Dolby® Model CP650 Installation Manual Front-Panel and Alignment Overview

Power Supply Button

This button operates the main power supply for the CP650. As with other Dolby cinema processors, the CP650 utilizes a separate backup (bypass) power supply. A red LED built into the switch is activated when the unit is powered from the bypass supply. While the main power supply is in use, this button is not illuminated, and the screen and other indicators operate normally. When this button is illuminated red, the unit is in bypass mode, either because bypass mode has been manually selected (by using the button) or because a fault has been automatically detected. In bypass mode, the unit is powered by the built-in bypass power supply.

Format Buttons

These buttons select the desired format. Pressing a format button during menu operations will return the display to the top-level menu.

Setup Control-Panel Access Door

For use by the service engineer, the access door is opened to expose the setup control panel.

Mute Button

Pressing the mute button fades the audio output to all channels without disturbing the current main fader setting. The speed of fade-in and fade-out is separately adjustable from 0.2 to 5 seconds using the front-panel menu buttons or PC setup software. The mute button flashes red when mute is activated.

Operation and Setup Menu Control Buttons

The menu control buttons are used by both the operator and the service engineer to navigate front-panel screen menus, select various menu options, and store setup data.

Figure 3–4 CP650 Operation and Setup Menu Control Buttons

The left-hand next menu button is used to step through the menu list. Pressing and releasing the button once will change the display to the next menu item. Pressing and holding the button while rotating the main fader knob will step the display through all menu items.

The center adjust parameter button is used to select a parameter to adjust when there are multiple items available on the display. Pressing and releasing the button will select among them. The adjustment is then made by rotating the main fader knob.

The right-hand OK button is used to accept the setting displayed on the front-panel screen and store it in CP650 memory. Any changes to settings will occur

3-5

Page 48

Dolby® Model CP650 Installation Manual Front-Panel and Alignment Overview

immediately, but will not be saved until this button is pressed. Leaving the current menu before pressing the button will cause the change to be discarded.

Note: For convenience, pressing the illuminated format button once, or any other format button twice, causes the CP650 to immediately return to the menu top-level screen display. This feature is handy for making a quick change, then returning to normal operation. This feature is not active in setup mode (described below).

3.2 The Setup Control Panel

The setup control panel is located behind the front-panel access door.

Wakeup projector 2

12233

Wakeup projector 1

MAIN

Video

Mic Bypass

MIC input level control

BYPASS output level control

Mic Phantom Power ON

Load baseline software during power-up

4455668

Clamp RTA1 RTA2

Test points used for alignment of the digital soundhead.

A laptop PC can be

Setup Mode

Dip Switch

LEDs indicate presence of an optical soundtrack signal.

SIGNAL PRESENT

Lt Rt

Test points used for connecting an oscilloscope to display CP650 RTA

Figure 3–5 Setup Control Panel

connected to this RS-232 data port. Windows-based set-up software is available for aligning the CP650. This connector is duplicated on the rear panel of the CP650.

SERIAL DATA MIC MUX

Connect a microphone multiplexer here or to the rear panel MIC INPUT connector.

Screw for removing the plastic front panel.

SwLCRLsRs

Channel signal output test points

3-6

Page 49

Dolby® Model CP650 Installation Manual Front-Panel and Alignment Overview

Mic Input Level Control

This ten-turn potentiometer has an end-to-end range of 46 dB. It is shipped from the factory set to minimum.

Bypass Output Level Controls

These two potentiometers, located on the Cat. No. 772A card, set the CP650 output level when the unit switches to bypass operation. The HF control is used if the CP650 is equipped with a Cat. No. 791 Crossover Card. Earlier units used the Cat. No. 772 (non-A) card with a single potentiometer.

Setup DIP Switch

The eight-position DIP switch is used to set the functions shown. All switches are factory-set to down. Switches 2, 5, 7, and 8 are not used. DIP switch 6 is used to enter CP650 setup mode.

Lt/Rt Signal Presence LEDs

These LEDs indicate that signals exist on the Lt and Rt sound channels from the film’s analog soundtrack. They flash during film playback in both normal and bypass operation.

Serial Communications Port (RS-232)

A laptop PC can be connected to this port using a straight-through (pin 1 to pin 1, pin 2 to pin 2, etc.) cable. A cable with receive and transmit lines swapped (null modem cable) will not work. Setup software is available for aligning the CP650. This connector is duplicated on the rear panel of the CP650.

Caution: The front- and rear-panel connectors are wired in parallel and should not be used simultaneously. Do not plug anything into the rear-panel connector if the front-panel connector is being used.

MIC MUX Connector

When setting up a CP650, a microphone multiplexer can be plugged into this connector (or to the XLR connector on the rear panel for some types of units).

Test Points

These test points are provided to allow rapid access to the required signals used during CP650 setup. Each test point is a 2 mm diameter female socket that accepts a 2 mm male test pin. Test point pins can be obtained in the USA from ITT Pomona® Electronics. Type 3221 is a useful, stacking, pin-to-BNC female adapter.

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Dolby® Model CP650 Installation Manual Front-Panel and Alignment Overview

3.3 Power Supply Voltage Test Points

Six test points are located behind the front-panel for measuring power supply voltages. They can be accessed by removing the front panel. See Section 9.3.1 for the voltage test ranges.

Main power supply DC test points: +15 V, –15 V, +5 V Bypass (“B”) power supply DC test points: +14 V, –14 V, +5 V

--15V

+15V

--14VB

MIC MUX

+5V

+14VB

+5VB

Figure 3–6 Power Supply Voltage Test Points

(A portion of the front subpanel, with front panel removed, is shown in this figure.)

3.4 Aligning the B-Chain and A-Chain

The B-chain is made up of system components from the main fader through to the loudspeakers. In the CP650, B-chain adjustments include speaker equalization, level settings, surround speaker delay settings, and mute fading time. If your CP650 is equipped with an optional Cat. No.791 Crossover Card, additional steps are required such as setting crossover points, filter types, and crossover slopes to select.

It is not practical for the entire cinema industry to standardize to a single make and model of loudspeaker. The different acoustical characteristics of individual theatres require individual speaker solutions. Therefore, electronic equalization of individual loudspeaker systems is used to achieve consistent results in a broad spectrum of environments, and with a broad range of speakers.

Accurate equalization requires the use of standardized acoustic measurement procedures.

The CP650’s built-in pink-noise generator provides a continuous random noise signal that covers the total bandwidth. This signal is used to measure and adjust the response of the loudspeakers. The use of random noise eliminates the problems inherent with the use of test tones (standing wave patterns in the theatres) and enables the frequency response of the entire system to be observed. Each channel can be measured and adjusted independent of the other channels.

A multi-microphone setup with multiplexer is placed in the auditorium to receive the pink noise reproduced by the loudspeaker. The output of the selected microphone is fed to a real-time analyzer (RTA) circuit built into the CP650 (or to your separate

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RTA if you prefer.) Equalization can be performed by using an oscilloscope connected to the RTA output test points or by using a PC running Dolby setup software. Either display will represent the spectrum received by the microphones. The effect of adjustments to the equalizers is quickly and easily seen. The Auditorium Assist

feature, available in system software version 2.0 and above, measures and

saves the auditorium characteristics for future checking. One of the problems inherent in equalization is the nature of the environment. In an

open space, a perfect loudspeaker, radiating a perfectly flat pink-noise response in all directions, placed in front of a perfectly flat microphone, producing perfectly flat response to sounds arriving from all directions, will display a perfectly flat response on the RTA output. In an enclosed space such as a theatre, the results are different. When the pink-noise generator is first turned on, all of the sound that initially reaches the microphone comes directly from the loudspeaker, and the response is flat—for a few milliseconds. Then, reflected sound from the walls, ceiling, floor, seats, and so on arrives at the microphone, together with the direct sound from the loudspeaker. This indirect, or reflected, sound reinforces the direct sound. The system soon settles into an equilibrium condition. As much energy is being absorbed by the walls, ceiling, and seats as is fed into the room. Since high- and mid-frequency energy is absorbed when sound is reflected, the displayed response appears to have a falling treble characteristic. At first glance, boosting the high frequencies may appear to be the logical solution to achieve a flat steady-state response, but such an arrangement works only on sustained sounds. Dialogue contains short, impulsive sounds that will yield a much-too-bright result because there is no time for reverberation to build and add to the original sound. A standard response curve is required that favors such impulsive “first arrival” sound and implies the same gently falling response that is observed when the output of an ideal loudspeaker is measured with a perfect microphone in the theatre.

The amount of reverberation varies with frequency. As frequency rises, more audio is absorbed rather than being reflected. A typical reverberation curve in a theatre rolls off at about 3 dB per octave above 2 kHz. This characteristic is used to define the standard steady-state response curve for all dubbing theatres in which films with Dolby soundtracks are mixed and for all Dolby processor-equipped cinemas.

The size of the theatre affects the reverberation time, and therefore the measurement of frequency response. After alignment to this standard curve, some slight adjustment of high-frequency slope may be necessary for extremely large or small theatres. The Bulk EQ Treble Adj. menu selection can be used to reduce the output by approximately 1 dB at 8 kHz for very a large theatre; or to increase the output 1 dB at 8 kHz for a very small theatre. Any such adjustment should be based on an evaluation, by ear, of actual known films rather than as a rule of thumb.

Some loudspeakers used in theatres are far from ideal and require boosting of the low- and high-frequency extremes in order to produce an approximation of the standard reference response curve. Bass and treble controls centered on the turnover points of typical loudspeakers lift the ends of the spectrum without the need for large amounts of narrow-band boost from the third-octave EQ circuitry.

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The final factor is masking of the screen. The masking curtains must be drawn back sufficiently to clear the left and right screen speakers before any adjustments or measurements are made. The high-frequency horns should clear the screen frame and be mounted as close as possible to the screen. Conventional black felt side-masking can severely restrict high-frequency response. Consequently, there would be severe losses if the left and right loudspeakers were equalized with the masking set for a

2.35:1 film, and then the masking were brought in for a 1.85:1 film, thus obscuring the outer speakers. To avoid this problem, some theatres have installed acoustically transparent masking cloth, and others leave the masking open whenever they are showing a 1.85:1 film with a stereo soundtrack. Moving the speakers towards the center of the screen to clear heavy masking is not a good solution, since the stereo separation would be degraded.

Repainted screens cannot be used for quality sound playback, because the perforations, which allow the high frequencies through the screen, can become clogged with paint.

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B-Chain Alignment

4.1 Check Theatre Equipment

Thoroughly check the loudspeakers and power amplifiers for any sources of poor performance, using the suggested checklists below as a guide.

Speakers

• Loudspeaker cables—Check that they are in good condition and that they are the

correct gauge for the impedance of the speakers and the length of the run.

• Speaker wiring—Check that the speakers are connected to the correct power amp

channel.

• Rattles—A leak in the low-frequency driver cabinet may sound like a rattle.

Chapter 4

• Also check for loose bolts or other hardware.

• Open drivers—In systems with pairs of drivers, one voice coil of the pair may be

open but the system will still function. Check the speakers with an ohm meter. If one channel requires markedly more equalization than the other, or if one speaker overloads at lower levels than the other speakers, an open driver circuit could be the cause.

• Check for missing drivers or other components.

• Crossover settings matching the type of drivers in use and the acoustics of the

theatre—The high-frequency driver level control must be set for the best possible frequency response before you attempt any equalization. This is especially true if the system uses active crossovers with bi-amp equipment. If your CP650 is equipped with a Cat. No. 791 Crossover Board, please refer to Section 4.4 for information on settings.

• Check for proper polarity between the low- and high-frequency drivers, and

between the channels.

• Aiming of speakers—Ensure that the speakers are correctly aimed into the

auditorium, and that they are not obstructed by the screen frame, struts, or other obstructions.

Amplifiers

• Check for distortion.

• Gross gain differences among amplifiers—If one amplifier differs in performance

from the others, it should be checked and repaired if necessary, before proceeding further. Input gain controls should all be at the same setting.

• Check for blown fuses.

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• Ensure that there is good air movement through power amplifiers.

Air-Conditioning

4.2 Microphone Placement

Position a microphone multiplexer in the center of the listening area. Place each microphone in the auditorium so that each is substantially in the reverberant field rather than in an area that receives the most direct energy from the speakers. In addition, avoid perfect symmetry. Arrange the microphones so that they are not arranged in a perfect square or rectangle parallel to the sides of the room. Take care not to place any of the microphones (except mic number 1) on the central axis of the room. Standing waves and nodes at these positions can cause measurement errors. Microphone number 1 should be placed two-thirds of the distance from the front speakers to the rear, at the exact side-to-side center of the room, approximately five feet above the floor level, and rotated 45 degrees upward towards the screen. Placement of this microphone is important for output level adjustments.

1.5 meters (5 feet)

Figure 4–1 EQ Microphone Placement

If a single microphone is used (NOT advised), the recommended position would be two-thirds of the way from the front speakers to the rear, off the axis of the center speaker, five feet above the floor level, and rotated 45 degrees upward towards the screen.

Route the output cable to the CP650 and connect it to the microphone connector on the rear panel or front setup panel (XLR on the rear panel or nine-pin D-connector “MIC MUX” input on front setup panel). The mic input connectors are wired in parallel. Phantom power is optionally provided to both mic connectors by moving DIP switch 3 to the up position.

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ll)

(Install)

4.3 Initial Setup

POWER AMPS

Off

Caution: The following steps will cause the CP650 to output pink noise to the power amplifiers. The CP650 output levels may be set too high. If you are unsure of the settings on your unit, turn off the power amplifiers before selecting the “Calibrate SPL” menu item shown in Section 4.4 below. Then, select and observe the present output level adjustment settings. (Press left menu button two times while the unit is in setup mode.)

Set all the gain controls on all power amplifiers to a known, repeatable setting . The

preferred setting for most amplifier gain controls is maximum.

If a different setting is required in order to optimize the noise performance of the system, the controls should be locked in position or marked clearly.

123 7456 8

Video

Clamp

RTA1 RTA2

Mic Bypass

Ch 1

Ch 2

GND

123 7456 8

ormat 10 (Insta

Dolby Digital

----- M 0

SIGNAL PRESENT

Oscilloscope

(Install)(Install)

Lt Rt

Connect an oscilloscope to the following test points located on the setup panel:

RTA1-to-scope channel 1 RTA2-to-scope channel 2

Set the oscilloscope to display both channels. Use the “chop” mode instead of “alt” mode for the best display results.

Apply power to the CP650.

Slide DIP switch-6 to the up position. This switches the CP650 into setup mode.

“(Install)” appears on the display screen.

If a microphone multiplexer is being used, select MIC 1.

MIC 1

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librate SPL

4.4 SPL (Sound Pressure Level) Calibration

If your CP650 is equipped with a Cat. No. 791 Crossover Board, an initial setup is required before you begin the SPL calibration. If you do not have a Cat. No. 791 installed, skip to Section 4.4.2.

4.4.1 Initial Setup (CP650s with Cat. No. 791 Crossover)

SPL calibration of CP650s equipped with a Cat. No. 791 Crossover Board is performed with the crossover set to “Full Range” mode. Pink noise is applied only to the CP650 low-frequency (LF) main outputs and these outputs are switched to fullfrequency operation for calibrating the CP650 to the room sound pressure level.

Press the left menu button four times to display the Crossover Mode screen.

Crossover Mode Full Range Crossover Disabled

One of three crossover configuration choices is displayed on the second line: Full Range, 2-Way, or 3-Way.

Rotate the front-panel knob until Full Range is displayed.

Press OK to save this setting.

4.4.2 Calibration Procedure (All CP650s)

Ca Enter Room Reading: > xx.x dB Press OK to continue

Press the left menu button twice to move the display to the Calib r ate SPL menu item.

Pink noise is sent to the center channel speaker.

Note: If pink noise is not being generated, this indicates that the status of the digital input has ch anged. If you are using the digital input on the CP65 0, either disconnect or power down the device attached the digital input during calibration. A change in the digital input bitstream will cause the CP650 to mute the pink noise.

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Mic L

OFF

The scope should now be receiving sync signals from the CP650. Set the scope vertical inputs to 100 mV/div. Set the horizontal sweep rate to 1 ms/div. Temporarily switch the inputs to GND and move the vertical position of each trace to line up with the bottom screen graticule line. Do not

move the vertical positions after completing this step. Switch the inputs to DC and adjust the

sync to trigger on the waveform. Adjust the scope horizontal position offset su ch that each displayed burst appears on the left and right-hand sides of the screen. If necessary, adjust the Mic input-level pot until the center area of the displayed pink noise moves to the middle of the scope screen.

With a sound pressure level meter, measure the noise level in the room. Rotate the front-panel knob until the room reading is shown on the frontpanel screen.

Note: Hold the sound pr essure level meter n ear the location of mic 1. The adjustment range is from 45 to 108.5 dB in 0.5 dB steps.

Please Wait...

Calibrating....

or Too High Proceeding Uncalibrated

evel Too Low

The CP650 is shipped from the factory with the Mic input-lev el control set to minimum.

Press the OK button. Wait while the system automatically calibrates to

the room reading.

Note: The calibration is retained in CP650 memory and can be used in future a lignments. However, it is advisable to recalibrate the system when re-a rranging microphones because the sound pressure level will vary slightly with microphone placement.

Note: The spect r um analyzer, built into the C P650, has automatic level c ontrol covering a ra nge of mic input levels. However, if you see an error message reporti ng mic level too low or too high:

The microphone(s) may require phantom power. Move DIP switch 3 up, press and hol d the left menu button, and rotate the main fader counterclockwise one step back to the Calibrate SPL Menu, and repeat the above steps.

While watching the oscilloscop e RTA display, adjust the Mic gain control to p lace the flat part of the signal in the approximate center of the screen. Th e trimpot is accessible through an opening in th e setup panel. Then press / hold the left menu button, and rotate the main fader counterclockwise one step back to the Calibrate SPL menu, and repeat the above s teps.

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Adjust Output L

4.5 Initial Output-Level Calibration

Each of the channels should now be adjusted to give a reasonable sound pressure level in the room. It is not necessary to get exact readings at this point because the levels will change slightly during equalization of the room. Exact output level adjustment will be performed after equalization.

Note: If pink noise is not being generated, this indicates that the status of the digital input has changed. If you are using the digital input on the CP650, either disconnect or power down the device attached the digital input during calibration. A change in the digital input bitstream will cause the CP650 to mute the pink noise.

4.5.1 Main Channels

Output Levels

>>>>Channel: Center Level: xx Room Level xx.x dB

After auto-calibration, the Output Levels adjust screen appears with Center Channel active.

Note: The RTA oscilloscope display is not active on this menu.

Press the center menu button, moving the cursor down one line to Level:

Note: The Level: line on the display shows a relative number. The number has no units.

Output Levels Channel: Center >Level: xx Room Level xx.x dB

Rotate the main fader knob to change the CP650 pink-noise output signal level into the auditorium

Channel: Center > Level: xx Room Level 85.0

85.0 dB

85.085.0

eve

while watching the measured Room Level shown on the bottom line of the display. Set it to 85 dB.

Note: If the room level does not appear, the calibration step may have failed or was n ot performed. Repeat Section 4.4.

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Adjust Output L

Output Levels >>>>Channel: Center Level: xx Room Level xx.x dB

>>>>Channel: Left Level: xx Room Level xx.x dB

Channel: Left >Level: xx Room Level 85.0

Right = 85 dB

Ls and Rs = 82 dB or

Ls, Bsl, Bsr, Rs = 82 dB

Saving Changes.....

...

Left

LeftLeft

85.0 dB

85.085.0

eve

Press the center menu button once to move the cursor back up to the Channel: selec tio n.

Rotate the main fader knob counterclockwise to change the Channel selection to Channel: Left.

Press the center menu button, moving the cursor down one line to Level:

Rotate the main fader knob to set the room level to 85 dB.

Repeat this process for the Right screen channel.

Repeat this process setting the Ls and Rs channels (Ls, Bsl, Bsr, and Rs channels if your unit is equipped with Dolby Digital Surround EX) to 82 dB.

When all channels have been adjusted, press the right-hand OK button.

“Saving Changes” appears on the front-panel screen.

Caution: If any other button is pressed, all of the settings will be lost!

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4.5.2 Subwoofer Channel

The initial subwoofer level adjustment uses a displayed RTA reference line, established from the center channel pink-noise level. The subwoofer level is adjusted to match the displayed reference line. Final subwoofer level adjustments for both digital and optical signal paths are carried out later, after the room is equalized.

Switch the microphone multiplexer to cycle. Press the left menu button once to move the

display one menu step. The Digital Subwoofer channel adjust menu appears next.

Digital Subwoofer >>>>Level: xx Polarity: Normal Center Noise: Off

Digital Subwoofer >Level:

>Level: xx

>Level:>Level: Polarity: Normal Center Noise: Off

Scope channel 2 displays a reference line.

Note: The RTA oscilloscope display is active on this menu.

Pink noise is now present on the subwoofer channel only (100 Hz bandwidth).

Using the front-panel knob, adjust the subwoofer channel level by moving the average subwoofer

Saving Changes.....

...

RTA display to the reference line displayed on the scope.

Press the right-hand OK button to save the level setting.

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4.6 Crossover Setup (CP650 with Cat. No. 791)

If your CP650 is not equipped with a Cat. No. 791 Crossover Board, please skip this section.

Two jumpers, located on the Cat. No. 772A board, must be set to “yes” when a Cat. No. 791 Crossover Card is installed. CP650s shipped with a Cat. No. 791 board have the correct jumper setting. See Section 9.3.2 for instructions on gaining access to the jumpers.

C DOLBY LABORATORIES INC. MADE IN THE U.S.A.

YES

Jumpers

Cat. No. 791 Crossover Board Present?

YES

Cat. No. 772A

MIC LEVEL

MAIN

BYPASS LEVELS

Figure 4–2 Cat. No. 772A Board Jumpers for Cat. No. 791 Crossover

The Cat. No. 791 Crossover Card contains a circuit in each high-frequency output channel (Left high, Right high, and Center high) to boost high frequencies. This allows the outputs to overcome the loss caused by placing the high-frequency drivers behind a perforated theatre screen. The circuit adds a maximum of 8 dB boost starting at approximately 6 kHz. This boost, combined with the bulk treble and equalization adjustments, provides enough high-frequency gain to suit most applications.

Since not all applications require this boost, jumpers are provided on the card to enable or disable it. The jumpers are set to disable at the factory. See Section 9.3.2 for instructions on gaining access to the jumpers.

Cat. No. 791 Screen Loss Filter Jumpers

ENABLE

DISABLE

LEFT

RIGHT

CENTER

Figure 4–3 Cat. No. 791 Board Jumpers for Screen Loss HF Boost

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The following parameters must be set before adjusting the room equalization in your auditorium:

• Crossover Mode (2-Way or 3-Way)

• Left Extra (Le) and Right Extra (Re) screen channel support

(available only in 2-Way and Full Range crossover modes)

• Filter type used at each crossover point (Linkwitz-Riley or Butterworth)

• Filter corner frequency at each crossover point

• Filter slope (Butterworth filter type only)

• Delay

• Polarity inversion to check for speaker wiring connections

Crossover Mode

rossover Mode

>3 Way

>3 Way>3 Way

Press the left menu button multiple times to move to the Crossover Mode menu.

Rotate the front-panel knob to select the crossover mode desired: 2-Way or 3-Way.

Note: Selecting Full Range mode disables the crossover outputs and switches the main channel outputs to full bandwidth for ca librating the SPL in the a uditorium (see Section 4.4.1).

Press the OK button to save your selection.

Le/Re Screen Channel Support

If your application calls for Le and Re support, the crossover must be operated in 2-Way or Full Range mode. In this case, the Le and Re outputs are full bandwidth. If these channels also require a crossover, you must use external units.

Le / Re Channels Disabled

Press the left menu button once to display the Le/Re Channels screen.

Rotate the front-panel knob to enable or disable Le/Re support.

Note: Le/Re screen channel support is available in 2-Way and Full Range mode only.

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Selecting Butterworth Filter Type

The crossover filters designed into the Cat. No. 791 are adjustable to allow tailoring of the response to your particular system. For most applications, the crossover filter type should be set to Linkwitz-Riley. The slopes in this filter are not adjustable. The filter has two cascaded two-pole Butterworth filters for the lowpass side, and a 3-pole filter for the high-pass side at the crossover point. The corner frequency for each crossover point is adjustable.

To customize the filter slopes, change the crossover filter type to Butterworth by following the steps below.

Move the display to the Crossover Configuration menu, by pressing the left

Crossover Config: >Channel: Left

>Channel: Left

>Channel: Left>Channel: Left Param : F Type Low Value : Lkwz.-Rly.

menu button multiple times, or by pressing and holding the button while rotating the front-panel knob.

Rotate the front-panel knob to select the channel that you wish to set up.

rossover Config:

Channel: Left >Param : F Type Low

>Param : F Type Low

>Param : F Type Low>Param : F Type Low Value : Lkwz.-Rly.

Press the center menu button to move the selection arrow to Parameter. This allows you to select which parameter you wish to set.

Rotate the front-panel knob to select the filter type (F Type.) The de faul t fi lte r ty pe is Linkwitz-Riley. If you wish to change the

Delay, Polarity Inversion

Select: Filter Type, Freq, Slope,

crossover filter slope to customize your application, the type must be changed to Butterworth by following the next steps.

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rossover Config:

Channel: Left Param : F Type Low >Value : Butterwth.

>Value : Butterwth.

>Value : Butterwth.>Value : Butterwth.

rossover Config: Channel: Left >Param : F Type High

>Param : F Type High

>Param : F Type High>Param : F Type High Value : Lkwz.-Rly.

rossover Config:

Channel: Left

Param : F Type Low

>Value : Butterwth.

>Value : Butterwth.>Value : Butterwth.

If you configured the crossover mode as 2-Way, there is one crossover point for setting the filter type. Press the center menu button to move the arrow to Value.

Rotate the front-panel knob to select the Butterworth fi lt er ty pe

If you configured the crossover mode as 3-Way, set the filter type for the highfrequency crossover point:

For a 3-Way crossover, press the center menu button to move the arrow to the Parameter selection, and rotate the frontpanel knob to select High for the mid-to-high crossover filter type.

Select the type of filter that you wish to use for the high-frequency crossover by pressing the center button to select Value.

Rotate the front-panel knob to select the Butterworth fi lter type.

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Setting Corner Frequency

Press the center menu button to move the arrow to the Parameter selection.

rossover Config: Channel: Left >Param : Freq Lo

>Param : Freq Lo

>Param : Freq Lo>Param : Freq Lo Value : 400

rossover Config:

Channel: Left Param : Freq Lo >Value : 400

>Value : 400

>Value : 400>Value : 400

rossover Config: Channel: Left Param : Freq Hi >Value : 1200

>Value : 1200

>Value : 1200>Value : 1200

Rotate the front-panel knob to select the lowpass filter corner frequency parameter (Freq Lo).

Press the center menu button to move the arrow to the Value selection.

Rotate the front-panel knob to select the desired corner frequency.

Press the center menu button two times to move the arrow back to the crossover Parameter selection.

If you configured the crossover mode as 2-Way, repeat the steps above to set the highpass corner frequency (Freq Hi).

If you configured the crossover mode as 3-Way, repeat the step above to set the mid-to-low (Freq M Lo), mid-to-high (Freq M Hi), and highpass frequencies (Freq Hi).

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Setting Butterworth Filter Slope

Crossover Config:

Channel: Left >Param : Slope Lo

>Param : Slope Lo

>Param : Slope Lo>Param : Slope Lo Value : 18

Crossover Config: Channel: Left Param : Slope Lo >Value : 18

>Value : 18

>Value : 18>Value : 18

Crossover Config: Channel: Left >Param : Slo

>Param : Slope Hi

>Param : Slo>Param : Slo Value : 24

pe Hi

pe Hipe Hi

If you selected Butterworth for the crossover filter type, press the center menu button twice to move the arrow to the Parameter selection.

Rotate the front-panel knob to select the low- frequency slope (Slope Lo).

Press the center menu button to move the arrow to the Value selection.

Rotate the front-panel knob to set the desired slope value.

Repeat the above steps to adjust the high frequency slope (2-Way), or the mid-to-low, mid-to-high, and high-frequency slopes (3-Way).

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Setting Delay

Crossover Config: Channel: Left

>Param : Delay Lo

>Param : Delay Lo>Param : Delay Lo

Value : 0.0 mSec

Crossover Config: Channel: Left

Param : Delay Lo

>Value : 0.0 mSec

>Value : 0.0 mSec>Value : 0.0 mSec

Crossover Config

Channel: Left Param : Delay Hi

>Value : 1.4 mSec

>Value : 1.4 mSec>Value : 1.4 mSec

The delay settings must be adjusted to compensate for different physical mounting positions of the speaker drivers.

Press the center menu button twice to move the arrow to the Parameter selection.

Rotate the front-panel knob to select the low-frequency output delay (Delay Lo).

Press the center menu button to move the arrow to the Value selection.

Rotate the front-panel knob to adjust the output delay, in milliseconds, for the lowfrequency output.

Repeat the steps above to adjust the highfrequency delay (2-Way), or mid-frequency and high-frequency delay (3-Way).

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Next Channel

Crossover Config: >Channel: Center

>Channel: Center

>Channel: Center>Channel: Center Param : F Type Low Value : Lkwz.-Rly.

Saving Changes.....

...

After all parameters have been set for this channel, press the center menu button to move the arrow to the channel selection, and rotate the front-panel knob to select the next screen channel to be adjusted. This example shows the center channel selected.

Repeat the steps above to set the crossover parameters for that channel.

When all crossover parameters have been set, press the OK button to save all settings.

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4.7 Room Equalization

Room equalization is performed using the real-time analyzer (RTA) circuit built into the CP650 along with an oscilloscope for RTA display. The adjustments for all output channels involves two steps: coarse, or “bulk,” adjustment using bass and treble controls, and fine adjustment, using a 27-band equalizer. Subwoofer channel equalization involves setting the frequency, “Q,” and level of “cut,” using a singleband parametric equalizer circuit.

If your CP650 is equipped with an optional Cat. No. 791 Crossover Board, there are additional steps to perform before setting room equalization. See Section 4.7.1 below.

The RTA screen on the scope displays a standard (ISO 2969) response curve. The ideal setting is reached when the room response readings fall on (or very close to) this standard curve.

Note: If pink noise is not being generated, this indicates that the status of the digital input has changed. If you are using the digital input on the CP650, either disconnect or power down the device attached the digital input during equalization. A change in the digital input bitstream will cause the CP650 to mute the pink noise.

4.7.1 Crossover Level Adjustment (for CP650s with Cat. No. 791)

If your CP650 is equipped with a Cat. No. 791 Crossover Board, perform the steps below before adjusting the bulk treble and bass settings in the next section. In order to properly set the levels of the various bands (low and high for 2-Way, or low, mid, and high for 3-Way systems), you must first adjust the levels of all bands to be approximately equal. By performing this adjustment first, the final amount of equalization required to match the standard response curve will be less.

Crossover Levels >Channel: Left Hi

>Channel: Left Hi

>Channel: Left Hi>Channel: Left Hi Level: 70

From the main format screen, press the left menu button multiple times to display the Crossover Levels screen.

Rotate the front-panel knob to select the

Left channel high-frequency output.

Note: With the crossover mode set to 2-Way or 3-Way,

each output (low, mid, and high) will affect the RTA display in the band set by the crossover corner frequency setti ngs. Each crossover out put level (mid and high) should be adjusted separately from the main level control in order to match the low-frequency output level.

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HF≈≈≈≈LF

MF≈≈≈≈LF

Crossover Levels Channel: Left Hi

>Level: 70

>Level: 70>Level: 70

Crossover Levels

>>>>Channel: Left Mid

Level: 70

Crossover Levels Channel: Left Mid >Level: 70

>Level: 70

>Level: 70>Level: 70

Crossover Levels >Channel: Center Hi

>Channel: Center Hi

>Channel: Center Hi>Channel: Center Hi Level: 70

Saving Changes.....

...

Mid

MidMid

Press the middle menu button to move the arrow to the Level selection.

While observing the RTA display on the oscilloscope, rotate the fron t-panel knob until the high-frequency bands are at the same approximate level as the lowfrequency bands.

If you configured the crossover mode as 3-Way, press the center menu button to move the arrow to the channel selection.

Rotate the front-panel knob to select the Left channel mid-frequency output.

While observing the RTA display on the oscilloscope, rotate the fron t-panel knob until the mid-frequency bands are at the same approximate level as the lowfrequency bands.

Press the center menu button to move the arrow to the channel selection, and repeat the above procedure for the remaining channels.

When all of the crossover level adjustments have been set, press the OK menu button to save your settings.

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>>>>

Bulk EQ Ch

Cent

4.7.2 Setting Coarse (Bulk) EQ

Bass Adjust:±x.x dB Treble Adj: ±x.x dB Corner Freq: x kHz

.: Center

enterCenter

Bulk EQ Ch.: Center >Bass Adjust

Bass Adjust:±x.x dB

Bass AdjustBass Adjust Treble Adj: ±x.x dB Corner Freq: x kHz

Press Left menu button.

The Bulk EQ menu appears with Center channel selected.

Pink noise will appear at the center channel speaker.

The standard response curve should appear over the average of the displayed mid-frequency peaks. If this is not the case, the scope setup step may have been performed incorrectly. See Section 4.3, first step.

Press the center menu button to move cursor down to Bass Adjust:

Slowly move the front-panel knob to adjust the low-frequency response as close as possible to the reference line displayed on the RTA.

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B-Chain EQ

Press the center menu button to move cursor down

Bulk EQ Ch.: Center Bass Adjust:±x.x dB >Treble Adj

Treble Adj: ±x.x dB

Treble AdjTreble Adj

Corner Freq: x kHz

1, 2, 4 kHz

L, R, and Ls, Rs

L, R, Ls, Bsl, Bsr, Rs

to Treble Adjust:

Slowly move the front-panel knob to adjust the high-frequency response as close as possible to the reference line displayed on the RTA.

If a satisfactory response is not obtained, try changing the corner frequency. Pressing the center menu button again moves the cursor to Corner frequency. The frequency selections are 1, 2, 3, or 4 kHz, and are set by rotating the frontpanel knob.

Adjust each of the remaining full-range channels by using the center menu button to move the cursor to Bulk EQ Ch.:, and front-panel knob to select the desired channel.

Note: Bulk equalization facilities for the surround channels are slightly different than for the scr een channels. The corner frequency is fixed at 2 kHz and is not changeable. There is also a 3 dB level shift to the standard response curve displayed on the scope.

Saving Changes.....

...

4.7.3 Setting Fine EQ (1/3 Octave)

Channel Select >>>>Center Press OK to continue

4-20

Caution: Do not press the left menu change button. All settings would be lost!

Press the right-hand OK button to save all bulk EQ settings.

Press the left menu button once to move to the B-Chain EQ menu. The software enters this menu with Center channel selected.

Press the OK button to begin final EQ on this channel.

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1.0kH

z C ±x.x dB

-_ _---_

--_- - - -__--_--

The 27-band RTA now displays on the oscilloscope.

1 kHz is the default start frequency band selected. A small marker on the scope trace shows the frequency band selected. Turn the front-panel knob (with no button pressed) to select the active

band. The CP650 screen cursor (line) blinks to indicate which band is active.

When the front-panel knob is rotated to selec t frequencies at the far left (or right) side of the LCD screen, the displayed bands will “scroll” left or right to show the low- or high-frequency bands.

Press and hold the middle menu button while moving the front-panel knob to adjust the level of the selected band. Perform fine adjustment of each

+ =

band adjusting the response to be as close as possible to the standard curve displayed on the scope.

All of the equalizer bands interact with each other. You should not start at the low-frequency end of the response curve and merely work your way to the high-frequency end. As each band is adjusted, the response of adjacent bands is affected. Start at the center frequencies. The desired curv e is a flat frequency response up to 2 kHz, falling at 3 dB per octave to 8 kHz (1 dB per third-octave band). If modern woofer systems (vented-box direct radiator enclosures) are installed in the theatre, moderate bass equalization may be used down to 40 Hz. Once an adjustment seems OK, work on the frequencies on either side of it. You may find that a cut at one frequency is followed by a slight boost at adjacent frequencies.

Shortcuts:

Spin the front-panel knob counterclockwise (more than 100 steps) to set the equalization to

= Flat

flat (no boost, no cut).

Spin the front-panel knob clockwise (more

than 100 steps) to activate the EQ Assist feature. See the description at the end of this

= EQ Assist

™

section.

Discarding Changes.. ...

Caution: Do not press the left menu change button unless you wish to reset your changes. All settings would be lost!

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Saving Changes.....

...

L, R, and Ls, Rs

L, R, Ls, Bsl, Bsr, Rs

4.7.4 The EQ Assist Feature

When the desired response for this channel has been achieved, press the right-hand OK button to save the settings.

Press the left menu button once, then move the front-panel knob to select the next channel to be equalized. Repeat the above procedure for the remaining full-range channels.

Figure 4–4 EQ Assist Operating Range

The EQ Assist function automatically adjusts the B-chain EQ levels in 22 bands, attempting to bring the spectrum of the audio in the auditorium in alignment with the standard response curve. Course (bulk) EQ must be performed before activating EQ Assist. (See Section 4.7.2.)

Activate EQ Assist by rotating the front-panel knob clockwise to move the blinking cursor up to the 16 kHz band. Keep spinning the knob clockwise. When the cursor stops blinking, EQ Assist is active and no further changes are allowed while it operates. You will see the levels moving, and hear the audio in the auditorium changing as the EQ Assist operates. When the cursor begins blinking again (after approximately eight seconds) EQ Assist has finished.

It is important to note that the lowest three bands of the graphic equalizer (40, 50, and 63 Hz) and the uppermost two bands (12.5 and 16 kHz) will not be adjusted. This is to protect the speakers against undesirable level boosts in those bands. Set these bands manually then verify that the overall equalization is satisfactory.

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Sub

4.7.5 Setting Subwoofer Channel EQ

woofer

woofer EQ

Subwoofer EQSubwoofer EQ >>>>Frequency: xx Hz Q: x.x Cut: - xx.x dB

Q = 2.0

Press the left menu button twice to move to the Subwoofer EQ screen.

Equalization facilities for the subwoofer channel are different than for the other channels. This process is designed to correct the principal room resonance in the operating range of the subwoofer. The subwoofer equalizer is a cut-only filter, with adjustable frequency (25 to 125 Hz), Q (center width, selectable between four values), and amount of cut (0 to 12 dB). There is no standard curve displayed for this function.

The center menu button is used to select Frequency, Q, or Cut, then the main fader knob to change the setting.

Press the center menu button to move the cursor to Q:, then rotate the front-panel knob to set Q to 2.0. This will produce a moderately wide notch.

Press the center menu button, moving the cursor to Cut:, then rotate the front-panel knob setting cut to 0.0 dB (minimum cut). This will disable the

Cut = 0.0 dB

EQ so that you can determine the low-frequency resonant peak to be equalized. The factory setting is 0.0 dB.

From the analyzer display, determine the primary low-frequency resonant peak of the room.

Rotate the front-panel knob counterclockwise to set Cut to maximum, 12 dB.

Cut = 12.0 dB

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Frequency

Press the center menu button to move the cursor to Frequency:, then rotate the fron t-panel knob. A dip in the frequency response will move along the frequency axis of the scope RTA display.

Cut

Saving Changes.....

...

Adjust the frequency until the center of the dip is in the same band as the peak displayed in the previous unequalized frequency response.

Press the center menu button to move the cursor to Cut:

Slowly reduce the amount of cut to flatten the dip displayed above. The center of the dip should be at the same level as the skirts.

Press the center menu button to move the cursor to Q:

Adjust Q for the flattest possible frequency response.

When the desired response has been achieved, press the right menu OK button to save the settings.

After saving the settings, the display returns the Subwoofer EQ screen.

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Digital Sub

4.7.6 Final Output-Level Calibration

Now that room equalization is complete, the sound pressure level in the theatre can be set accurately.

Main Channels

If a microphone multiplexer is being used, select MIC 1.

MIC 1

Output Levels

>>>>Channel: Center Level: xx Room Level xx.x dB

L, C, R = 85 dB

Ls and Rs = 82 dB or

Ls, Bsl, Bsr, Rs = 82 dB

Press the left menu button to display the Output Levels screen.

Repeat the output level setting steps given in Section 4.5.1, starting with the second step in that section.

Note: Since the sound pressure level calibration was performed earlier, a recalibration is not required unless the microphone placement has changed. Repeat the steps in Section 4.4 if necessary.

Digital Subwoofer Channel

Digital Subwoofer

ital Subwoofer Digital Subwoofer

Di >>>>Level: xx Polarity: Normal Center Noise: Off

woofer

Digital Subwoofer >Level:

>Level: xx

>Level:>Level: Polarity: Normal Center Noise: Off

Saving Changes.....

...

Switch the microphone multiplexer to cycle.

Press the left menu button once to move the display one menu step to Digital Subwoofer

Level.

Note: The RTA oscillos cope display is active on this menu. If

the reference line does not appear, the calibration step may have failed or was not performed. Repeat the SPL steps in Section 4.4.

Pink noise is now present on the subwoofer channel only (100 Hz bandwidth).

Using the front-panel knob, adjust the subwoofer channel by moving the average subwoofer RTA display to the reference line display ed on the scope.

Press the right-hand OK button to save the final level setting.

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Optical Sub

Note: If pink noise is not being generated, this indicates that the status of the digital input has changed. If you are using the digital input on the CP650, either disconnect or power down the device attached the digital input during level setting. A change in the digital input bitstream will cause the CP650 to mute the pink noise during level setting.

Optical Subwoofer Bandwidth

This menu item sets upper frequency limit of the subwoofer channel to either 50 or 100 Hz. The recommended setting depends on the type of screen speakers in your cinema. If you have direct radiator type screen speakers, set the bandwidth to 50 Hz. If you have the older horn-loaded type of screen speakers (such as Altec A-4), set the bandwidth to 100 Hz.

Optical Subwoofer Bandwidth > 50 Hz

Press the left menu button once to move the display one menu step to the Optical Subwoofer Bandwidth.

Rotate the front-panel knob to select the desired

50 Hz / 100 Hz

Saving Changes.....

...

bandwidth.

Press the right-hand OK button to save the selection.

Optical Subwoofer Channel Level

woofer

tical SubwooferOptical Subwoofer Level: xx Polarity: Normal Center Noise: Off

Optical Subwoofer >Level

>Level: xx

>Level>Level Polarity: Normal Center Noise: off

woofer

Press the left menu button once to move the display one menu step to the Optical Subwoofer Level setup menu. Pink noise is now present on the subwoofer channel only.

Rotate the front-panel knob to move the average level of the displayed pink noise up or down to the meet the reference line.

Note: The RTA oscilloscope level referen ce line displa ys 10 dB lower for this adjustment and the pink-noise generator bandwidth is 50 Hz for the optical subwoofer setup. If the reference line does not appear, the calibration step may have failed or was not performed. Repeat the steps in Section 4.4.

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Subwoofer Speaker Polarity Check

Optical Subwoofer

Level: xx Polarity: Normal >Center Noise: On

OnOn

Polarity:

Normal / Inverse

20–80 Hz

Saving Changes.....

...

Level

Using the center menu button, move the cursor to Center Noise, then rotate the front-panel knob to On.

Press the center menu button to move the cursor to Polarity:

Use the front-panel knob to switch between Normal and Inverse polarity.

Note the change in the average level of the RTA bands between 20 and 80 Hz. There should be a level DECREASE when the polarity is Inverse. The polarity of the subwoofer wiring is incorrect if you do not see a decrease. In this case, reverse the subwoofer speaker wiring connections.

If the subwoofer wiring polarity is correct, you will see a level increase between 20 and 80 Hz on the RTA display when the front-panel knob is rotated to Normal.

Press the right OK button to save the settings.

Note: The subwoofer polarity will always be reset to the “normal” setting. “Inverse” is a temporary setting for this test only.

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Rotati

CAUTION

4.8 Final Sound Check: Rotating Pink Noise

123 7456 8

ressing OK will play pink noise in the auditorium

ng Noise Press OK to Start or Stop Running L

Slide DIP switch 6 down to the normal position. The CP650 will switch to normal operation with the user’s menu choices available.

Press the left menu button multiple times to move the display to the Rotating Pink Noise screen.

Press the right OK button to start the pink noise.

Pink noise is sent to each channel in turn, holding for five seconds at each channel. The channel currently running pink noise is shown on the bottom right-hand side of the display.

Unlike the different levels used during alignment, the rotating pink noise is set to 85 dB for all channels during this test.

Pressing the right OK button stops the pink noise from moving to the next channel. Pressing the OK button again resumes pink-noise rotation.

Go to the auditorium and sit two-thirds of the distance from the front speakers to the rear, and at the center from side-to-side. All channels should sound equally loud and have similar frequency response as the noise rotates. An SPL meter can be used to confirm accurate and equal level settings.

Press the illuminated format button to return the CP650 to normal operation.

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5.1 Overview

The A-chain alignment involves adjustments made to the projector soundhead optics, solar cell, and optical preamplifier board. It is the part of the sound system that covers the film path, analog soundtrack solar cell, optical preamplifier, slit-loss equalizer, digital soundtrack reader, associated digital signal processing and decoding circuitry, and Dolby

The A-chain optical level is calibrated with the Cat. No. 69T Dolby Tone test film. This film is used to establish the correct Dolby operating level within the CP650.

processing circuits.

Chapter 5

A-Chain Alignment

A Cat. No. 69P pink-noise test film is used for A-chain frequency response and soundhead alignment. Pink noise has a constant amount of energy per 1/3-octave band, creating a flat response on a real-time analyzer display.

The optical slit is the key element in the A-chain because it imposes the initial limitation on the high-frequency response of the system. Light from the exciter lamp passes through the optical slit and is focused on the optical soundtracks on the film. The light that passes through the soundtracks falls on the stereo solar cell, which generates an electrical signal proportional to the audio signal recorded on the optical soundtracks. The slit introduces high-frequency loss, which must be compensated by circuitry in the CP650.

The slit image must be correctly focused on the film and must be set at precisely a right angle to the direction of film movement in order to maintain the correct phase relationships between the two optical tracks. Any azimuth error will show as a loss of high frequency in the front channels and potentially excessive crosstalk in the surround channels.

Each channel in the CP650 optical preamplifier is equipped with a slit-loss equalizer control. Adjustment of this control shifts a fixed amount of boost upward or downward in frequency, but the shape of the curve remains constant. A flat response to 16 kHz can be achieved.

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5.2 Reverse-Scan Checkup: Projector

Clean the optical surfaces with a cotton swab moistened with glass cleaner. Inspect the film guides for evidence of cuts, cracks, surface defects, or any foreign materials that could impair smooth film guiding.

5.3 Analog Optical Alignment: Projector

If a stereo solar cell is already installed on Projector No. 1, inspect the surface of the cell for cracks, chipping, or other damage. If the cell appears to require replacement, remove the mounting bracket from the projector and replace the cell and mounting block assembly.

Clean the lens surfaces with a cotton swab moistened with glass cleaner. But keep in mind that you may find, during optical preamp adjustment, that it will be necessary to remove and inspect the lens if the high-frequency response is not correct.

If the lens is removed, clean the lens as indicated above and look through the lens at a light. Repeated heating and cooling of the lens can cause oil or other contaminants to enter the lens barrel. Verify that ther e is a clear, unobstructed light path through the lens and that the edges of the slit are sharp without cracks or corrosion. Fit a new lens assembly if you are unable to clear the optical path through the slit.

Inspect the lateral film guides for evidence of cuts, cracks, surface defects, or any foreign materials that could im pair the fi lm guiding. Clean or replace the guides as necessary. The guide roller must rotate freely; if it is springmounted, make sure that lateral movement and return are not obstructed. If the roller has a felt or rubber insert, check for a flat spot and replace the roller if necessary .

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Remove the existing exciter lamp and replace with a new lamp.

Adjust the exciter lamp DC voltage to between 70 and 85 percent of the rated voltage. Using an AC millivolt meter or oscilloscope, verify that there is no more than 3 percent ripple present with the lamp on.

LAMP VOLTAGE DC ADJUSTMENT

6 V 4–5 Volts 9 V 6.5–8 Volts

If the projector uses a plastic light pipe or tube, verify that the light output is not appreciably affected by dirt, cracks or flaws, yellowing, or foreign matter. Replace if necessary.

Place a white card at the front of the lens close to the position of the film sound track. Adjust the position of the exciter lamp until the image of the filament is centered both vertically and horizontally as shown.

If you have difficulty obtaining an image of the filament, place a piece of tissue paper over the lens to assist in seeing the image. Some projectors do not use adjusting screws to change the position of the lamp; shims are sometimes used for positioning.

Loosely install the stereo solar cell bracket on the projector. Position the bracket carefully until the surface of the cell is 1 mm from the film plane surface. If this distance is exceeded, there will be crosstalk between the two optical stereo tracks. Check the image of the slit on the cell: It should be a thin sharp line. The slit image should be the width of the cell, and positioned three-quarters of the way up the cell. Try to get the best compromise among all of these conditions and then tighten the cell bracket mounting screws.

Confirm that the cell wiring and connections are correct. Shielded cables must be used. The inner conductors must be wired to the CP650 OPTICAL input connectors exactly as shown on the wiring diagram foldout.

5-3

Note: The solar cell associated with the right channel is closest to the edge of the film.

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Aut

5.4 Dolby Level Set

Connect the oscilloscope to the Lt and Rt test points.

123 7456 8

Slide DIP switch 6 to the up position. This switches the CP650 into setup mode.

Mic Bypass

123 7456 8

Video

Clamp

Ch 1

Ch 2

GND

RTA1 RTA2

SIGNAL PRESENT

Lt Rt

Oscilloscope

omatic Optical Level Adjust Projector 1 Press OK When Ready.

Press the left menu button multiple times to move the display to Automatic Optical Level Adjust Projector 1.

Thread and play a Dolby Tone test film, Cat. No. 69T on projector 1. The film emulsion should face away from the screen.

Verify that the signal presence LEDs on the CP650 setup panel are illuminated. The Dolby tone signal should be visible on the oscilloscope.

Proj 1

Listen to the tone on the booth monitor to identify any problems with distortion or unwanted film playing speed variations.

L O O Please Wait. O O

....... O O

O O

Press the OK button to begin the automatic level calibration for projector 1.

Perform automatic calibration for Projector 2 if the theatre is equipped with a second projector.

Unable to complete Level adjustment. Press OK to continue

If there is a problem with automatic calibration, this screen will appear.

In this case, press the OK button to return to the Automatic Optical Level adjust screen,

then press the left menu button twice to move to Manual Optical Level Adjust for Projector 1.

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anual L O O R Level O O P1

XX O O

XX XX

O O

anual L O O R Level O O P1

O O

O O xx

xxxx

Saving Changes.....

...

Press the OK button to begin manual adjustment.

The number displayed on the bottom line represents the level setting for Left channel. The four vertical circles display the Left channel signal level, similar to an LED meter.

Rotate the front-panel knob until the two center circles fill black.

Press the center menu button to select the Right channel.

The number displayed on the bottom line will move the Right-channel column.

Rotate the front-panel knob until the two center circles fill black.

Press the OK button to save the level settings.

Stop the projector and load/run Cat. No. 69T film loop on projector 2, if so equipped.

Proj 2

Press the left menu button to move the displayed menu to Manual Optical LevelAdjust for projector 2.

anual Optical Level Adjust Projector 2

Projector 2

Projector 2Projector 2 Press OK when ready.

Repeat the above procedure for the Left and Right channels.

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Saving Changes.....

...

Press the OK button to save the level settings for Projector 2, Left and Right channels.

5.5 Film-Path Alignment Check

Connect the oscilloscope to the Lt and Rt test points.

Mic Bypass

123 7456 8

Video

Clamp

RTA1 RTA2

SIGNAL PRESENT

Lt Rt

Ch 1

Ch 2

GND

Oscilloscope

Thread and play a SMPTE Buzz Track test film. This film has modulation just beyond the normally scanned areas of the optical sound tracks. The objective of this test is to ensure that the slit illuminates only the soundtracks.

Proj 1

The method of positioning the slit relative to the optical tracks varies with the design of projector installed. In many cases, the film guide is adjusted laterally for a null if the lens and exciter lamp are fixed in position. If the film guide cannot be moved, then adjust the lens and LED/exciter lamp assembly laterally.

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The adjustment is correct when there is no

✓

L RR

✓

signal output while the film is running. not be possible to adjust for a null with some older slits; in such instances, adjust for a minimum and equal signal on L and R.

Some projectors use a lens with an adjustable slit width. point when the left and right signals both disappear equally.

The adjustment is correct at the

It may

OSCILLOSCOPE TRACES

5.6 Cell Alignment Check

Remove the SMPTE Buzz Track test film and thread and play the Cat. No. 97 Stereo Cell Alignment Film.

If a large amount of crosstalk is present on the scope display, loosen the stereo solar cell head and move it from side to side until the crosstalk is minimum and equal.

Lock the cell bracket into position after completing this adjustment. Check that the crosstalk does not change as the bracket is tightened.

Note: The Right channel is the track toward the outside of the projector. On some projectors, it may be necessary to stop the film to adjust the position of the cell.

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5.7 Cell Wiring Check

Verify that the outputs of the right and left solar cells are properly connected by placing a white card over the right sound track (nearer the outside of the projector) and verifying that the level of the Right channel drops, as indicated by the Rt Signal Present LED on the CP650 setup panel.

If the film path, optics, or LED / exciter lamp were adjusted, repeat the previous filmpath alignment and cell alignment steps.

The optimum setting is attained when no

further adjustments are required using the two test films.

5.8 Azimuth Check

✓

Correct

Out of phase

Thread and play the Cat. No. 69 P pink-noise test film.

Switch the oscilloscope to the X/Y mode and adjust the azimuth of the projector optics for the narrowest diagonal trace.

x x

Not enough light

on one channel

Also, if the ends of the trace d isplay thicker than the center area, then improper lighting of the edges of the optical tracks should be corrected.

Note: If necessary, repeat the buzz track and cell alignment steps or LED/exciter lamp p o sition steps above to reduce such blooming to a minimum.

Uneven light on cell

Incorrect azimuth

5-8

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5.9 Focus Check

Mic Bypass

123 7456 8

Video

Clamp

Ch 1

Ch 2

GND

RTA1 RTA2

SIGNAL PRESENT

Lt Rt

Reconnect the scope to RTA1 and RTA2 test points.

Oscilloscope

Optical Focus >Projector: P1

Channel: Left Press OK when ready.

Press the CP650 left menu button to move to the Optical Focus adjust menu.

The scope RTA will display the frequency response of the Left channel optical preamp output for projector 1.

= Projector or Channel

The center menu button selects the projector or channel.

The front-panel knob selects P1/P2, or

= Select P1 then Left/Right

Left/Right channel to view. Select projector 1.

With the pink-noise test film running, observe the high-frequency response displayed on the scope.

Adjust the focus of the sound track lens for the

Left / Right Channels:

best high-frequency response on both the left and right channels.

The RTA trace shown may not be typical of your results.

Merely attempt to obtain the best

response. The azimuth and focus adjustments interact so you must repeat the azimuth and focus adjustments until no further improvement is obtained. Do not proceed to

the next step until both the left and right results are similar.

Projector 2

Repeat the focus adjustment for projector 2.

Left/Right

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Auto Slit

Slit

5.10 Optical HF Equalization (Slit-Loss EQ)

This step adjusts the high-frequency response of the optical preamplifier circuit. The CP650 provides both automatic and manual facilities for optical, or slit-loss, highfrequency equalization. The Auto menu appears first:

Auto Slit-Loss EQ

Continue to play the Cat. No. 69 P pink-noise test film.

Projector 1:

Projector P1 Press OK when ready.

Level Adjust done. Press OK to save the

current settings.

oss

P1P1

oss

Move the CP650 menu display to Auto SlitLoss EQ for Projector 1.

Press the OK button to begin automatic equalization. The HF response on both the Left and Right channels are automatically equalized. You can observe the action on the scope RTA display. Dots shown on the frontpanel display show progress. When the dots reach the end of the line, the Right channel is automatically equalized.

When EQ is completed, as shown on the display, press the OK button to save the settings.

Press the left menu button to move to the Projector 2 menu and repeat the procedure above if a second projector is installed.

Manual Slit-Loss EQ

Projector 1:

anual Projector 1 >>>>Channel: Left Value: xx

Left / Right

Adjust EQ

oss

The next menu is used for manually adjusting the slit-loss EQ.

Use the center menu button to chose between the channel to be adjusted and the setting (value).

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Slit

Rotate the front-panel knob for the most extended high-frequency response without

“peaking.”

Note: If this procedure does not improve the response, the problem may be a degraded slit or lens damage.

Saving Changes.....

...

Projector 2:

anual Projector 2 >>>>Channel: Left Value: xx

oss

When the desired response has been achieved, press the right menu OK button to save the settings.

After saving the settings the display returns the Manual Slit-Loss EQ Projector 1 menu.

Press the left menu button to move to the Manual Slit-Loss EQ Projector 2 menu and repeat the procedure above.

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Digital Soundheads

6.1 Mechanical Alignment

Mechanical alignment of the Cat. No. 701 (or 700) Digital Soundhead consists of confirming that the film path through the digital soundhead is aligned with the path through the projector. For built-in reverse-scan (basement) digital soundheads, see the manufacturer's instructions.

1. Thread a length of film from a supply reel through the digital soundhead (refer to the threading diagram located on the soundhead), and continue through the projector as you would any film.

2. Apply tension to the film and inspect for equal tension on both edges of the film.

3. Check for uneven forces on the rollers, or twisting of the film.

4. When the path is aligned, tighten the soundhead mounting bolts and reel arm.

Set film path so that top and bottom tension arm rollers are approximately 5 mm (1/4 inch) apart. Use the white painted semi-circles for angular alignment of tension arms . Make sure that the rollers do not touch.

Chapter 6

Dolby Digital Print Threading Path Bypass Threading Path

Figure 6–1 Digital Soundhead Adjustments

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6.2 Adjustment with Oscilloscope

Note: The Cat. No. 701 Digital Soundhead is optically aligned at the factory and should not require adjustment unless the CCD Circuit Board has been disturbed.

The following test setup will enable adjustment of focus and confirmation or adjustment of light level and optical alignment.

1. Make sure power to the digital soundhead is provided. Power to the CP650 should also be on.

2. Open the CP650 front-panel setup access door.

3. Connect a probe from Channel 1 of an oscilloscope (with 20 MHz or greater bandwidth) to the VIDEO Test Point, with the ground lead attached to the ground test point.

4. Connect a second probe from the scope’s Channel 2 to the CLAMP signal test point to trigger the scope. Connect the second probe’s ground wire to the ground test point.

5. Set the trigger source on the scope to Channel 2.

6. Adjust the Channel 2 vertical trace position to move the trace off the screen. It is not necessary to view this signal after triggering has been established.

7. Adjust the scope for one horizontal trace across the screen, and adequate vertical gain (approximately 2 µs/div. horizontal, 1 V/div. vertical).

8. With digital film threaded and running in the projector, observe the video waveform. (See Figure 6-2.)

6.3 Focus Adjustment

Cat. No. 701 (or 700) Digital Soundheads are factory adjusted and should not require adjustment during installation. If the soundhead has become misadjusted, it may be necessary to re-focus. Using the setup as above, adjust the objective lens/CCD assembly in the reader head by loosening the 2 mm hex socket set screw (located below the lens bore), which holds the lens/CCD assembly in place, then moving the assembly back and forth. There are two methods for moving the assembly. A flat blade screw driver inserted in the oval slot above the lens can be twisted to slide the assembly. Alternatively, if the CCD circuit board cover is removed, the assembly can be moved back and forth with your thumb and forefinger. The best focus is achieved when the scope pattern has minimum brightness in the center of the trace. (See Figure 6-2.) Look for the most “in-focus” display possible, while maintaining minimum brightness inside the envelope. Setting the best focus will help minimize the digital error rate.

Re-tighten the lens-holding screw.

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Dolby® Model CP650 Installation Manual Digital Soundheads

Figure 6–2 Digital Video Oscilloscope Image—Focus Adjustment

6.4 LED Brightness Confirmation and Adjustment

The optimum peak video signal voltage (unobstructed light through the perf hole) is 4 V, measured from the 0 V reference baseline to the upper trace. If necessary, adjust the Cat. No. 701 power supply output to achieve the correct video voltage. See Figure 6-3 for adjustment location (VR1). The back cover of the digital soundhead must be removed to gain access to the output adjustment.

Output Adjust

(VR1)

Figure 6–3 Cat. No. 701 LED Brightness Adjustment

6.4.1 Inboard Digital Readers

There are several varieties of basement readers, some use lamps, and some use LEDs as the illumination source. Refer to the instructions for the built-in reader for details on adjusting lamp/LED current. In any case, the proper video level is 4 V. If the top of the video waveform is not reasonably flat (±1 division), check for dirt, dust, or other obstruction to the light path, and clean.

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Dolby® Model CP650 Installation Manual

Adjust

Final Adjustments

7.1 Setting Bypass Level

With a Cat. No. 791 Crossover Card installed, two jumpers, located on the Cat. No. 772A card, must be set to “Yes”. This enables the Cat. No. 791 card bypass output and sends a full-range signal to the hearing-impaired output. CP650s shipped with a Cat. No. 791 card have the correct jumper settings. See Figure 4–2 .

123 7456 8

Chapter 7

MAIN

Mic Bypass

DIP switch 6 up

ypass Level

Press OK to enter bypass.

Normal Bypass

123 7456 8

Video

Clamp RTA1 RTA2

SIGNAL PRESENT

Lt Rt

SERIAL DATA MIC MUX

Ensure that DIP switch 6 is in the “up” position

Press the left menu to move the Bypass Level Adjust menu (or press and hold while rotating the front-panel knob).

Press the OK button, switching the CP650 to bypass operation. The main power button will illuminate, confirming that the unit is in bypass.

Thread and play a loop of Cat. No. 69P pink-noise test film.

Using the OK button, toggle back and forth between normal and bypass operation, while setting the MAIN bypass level trimpot (located through the access hole on the setup panel).

Adjust the pot until the audio level in the

SwLCRLsRs

auditorium sounds the same for normal and bypass.

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Dolby® Model CP650 Installation Manual Final Adjustments

If your CP650 is equipped with a Cat. No. 791 Crossover Card:

Follow the previous steps to set the Main bypass level trimpot for correct low-frequency level matching.

MAIN

Mic Bypass

123 7456 8

Video

Clamp RTA1 RTA2

SIGNAL PRESENT

Lt Rt

SERIAL DATA MIC MUX

SwLCRLsRs

With the unit in bypass, adjust the HF bypass level trimpot for correct low/high-frequency balance. A real-time analyzer should be used for accurate setting.

Verify that the audio level in the auditorium sounds the same when in normal and bypass

Normal Bypass

modes by using the OK button to toggle back and forth between normal and bypass.

When finished, leave the CP650 in normal

operating mode (Power button not showing red).

Optical Surround Level Trim

It is recommended that you perform this adjustment. (See Appendix C.)

7.2 Setting Optical Surround Delay

In analog optical formats, the CP650 incorporates a delay line in the surround channel to ensure that sound from the rear of the theatre arrives at the listeners’ ears approximately 20 milliseconds after the arrival of sound from the front speakers. The delay is adjustable from 20 to 150 ms, in 1 ms steps. The setting is stored to CP650 memory using the procedure outlined below. Use the following formula to calculate the correct delay setting:

1. Estimate the distance between a rear seat and the nearest surround loudspeaker, in feet. If the metric system is used, multiply the meters by 3 to convert to feet.

2. Estimate the distance from this seat to the front loudspeakers (again, in feet). If the metric system is used, multiply the distance by 3 to convert distance from meters to feet.

3. Subtract the distance measured in step 1 above from the distance measured in step 2, then add 20. The result is the delay time, in milliseconds.

For example:

• The selected seat is 10 feet (3.3 meters) from the nearest surround speaker.

• The selected seat is 80 feet (26.7 meters) from the front speakers.

• The delay is set for (80-10) + 20 = 90 milliseconds.

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Dolby® Model CP650 Installation Manual Final Adjustments

Optical S

Press the left menu button to move to the Optical

Delay > xxx mSec

urround

Surround Delay menu.

Rotate the front-panel knob to show the desired delay, then push the OK button.

You can verify that the delay setting is acceptable by listening to a familiar Dolby® A-type film that ideally contains both center-channel dialogue and some discernible surround sound. The Dolby Cat. No. 251 SR/Digital film “Jiffy” serves this purpose well. If a stereo film is not available, the delay time can be checked with a mono film if the film is played in Format 04, Dolby A-type optical with surround. All speakers should be on for this test.

While the film is playing, walk around the theatre and listen carefully to the surround speakers during center-channel dialogue. The dialogue should appear to be coming primarily from the screen, and not from the surround speakers.

If you hear discernible dialogue from the surround speakers, the delay time was probably set too long.

If you hear an objectionable amount of dialogue from the surround speakers that persists regardless of the delay time setting, there is probably a severe gain or azimuth error in the system. Re-check both the Dolby level and the A-chain alignment of the optical system.

In many films, the surround information is intended for subtle effects and may provide only a low-level ambience. If the surround level and delay time have been adjusted as previously described, the surround information will be at the level desired by the film director. Do not be tempted to increase the surround level, because the effect desired by the film production team may be thwarted.

7.3 Setting Digital Surround Delay

The CP650 automatically calculates a typical digital surround delay based on the optical surround delay setting performed in the previous section. Actual theatre geometry affects the amount of surround delay required; you may, therefore, wish to set the delay manually.

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Dolby® Model CP650 Installation Manual Final Adjustments

Digital S

Press the left menu button to move to the Digital

Delay > xxx mSec

urround

Surround Delay menu.

Rotate the front-panel knob to show the desired delay then push the OK button.

Tables 7–1 and 7–2 show approximate delay values (in milliseconds) based on theatre width and length. Setting of surround delay should be verified by listening at various locations in the theatre.

Table 7–1 Surround Delays Based on Theatre Dimensions (in Feet)

Width (feet)

20 30 40 50 60 70 80 90 100 110 120 130 140

10 10 10 10 10 10 10 10 10 10 10 10 10

20 20 20 20 20 20 20 20 20 20 20 20 20

30 20 20 20 20 20 20 20 20 20 20 20 20

30 30 30 30 30 30 30 30 30 30 30 30 30

40 30 30 30 30 30 30 30 30 30 30 30 30

50 40 40 40 40 40 40 40 40 40 40 40 40

50 50 40 40 40 40 40 40 40 40 40 40 40

90 100 110 120

Length (feet)

130 140 150 160 170 180 190 200

60 50 50 50 50 50 50 50 50 50 50 50 50 70 60 60 50 50 50 50 50 50 50 50 50 50 70 70 60 60 50 50 50 50 50 50 50 50 50 80 80 70 70 60 60 60 60 60 60 60 60 60 90 80 80 70 70 60 60 60 60 60 60 60 60

90 90 80 80 80 70 70 70 70 70 70 70 70 100 100 90 90 80 80 70 70 70 70 70 70 70 110 100 100 90 90 80 80 80 80 80 80 80 80 110 110 100 100 100 90 90 80 80 80 80 80 80 120 120 110 110 100 100 90 90 90 90 90 90 90 130 120 120 110 110 100 100 100 90 90 90 90 90

7-4