Dolby Laboratories SDU4 User Manual

MAIN

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Model SDU4

Surround Decoder

User's Manual

Issue 2 Part No. 91413

User's Manual

MAIN

Model SDU4

Surround Decoder

Dolby Laboratories Incorporated

U.S.A. 100 P otrero Avenue, San Francisco, CA 94103-4813

Tel: 415-558-0200; Fax: 415-863-1373; Web: www.dolby.com

U.K. Wootton Bassett, Wiltshire SN4 8QJ

Tel: (44) 1793-842100; Fax : (44) 1793-842101

DISCLAIMER OF WARRANTIES

workmanship for a period of one year from the date of purchase. All warranties, conditions or other terms implied by statute are excluded to the fullest extent allowed by law.

LIMITATION OF LIABILITY

negligence or otherwise shall not exceed the cost of repair or replacement of the defective components and under no circumstances shall Dolby Laboratories be liable for incidental, special, direct, indirect or consequential damages (including but not limited to damage to software or recorded audio or visual material), or loss of use, revenue or profit even if Dolby Laboratories or its agents have been advised, orally or in writing, of the possibility of such damages.

Dolby and the double-D symbol are registered trademarks of Dolby Laboratories

: Equipment manufactured by Dolby Laboratories is warranted against defects in materials and

: It is understood and agreed that Dolby Laboratories’ liability wh ether in contract, in tort, under any warranty, in

SDU4-CE

Issue 2

Part No. 91413

MAIN

TABLE OF CONTENTS

SECTION 1–INTRODUCTION............................................................................................. 1-1

1.1 The SDU4 ......................................................................................................................... 1-1

1.2 Specifications .................................................................................................................. 1-2

1.3 Regulatory Notices ....................................................................................................... 1-3

SECTION 2–INSTALLATION & CALIBRATION........................................................... 2-1

2.1 Monitor Setup ................................................................................................................. 2-1

Front Loudspeaker Arrangement ......................................................................... 2-1

Surround Loudspeakers.......................................................................................... 2-2

Equalization............................................................................................................... 2-2

2.2 Mains Fuse and Voltage Selection.............................................................................. 2-2

2.2.1 230V-Only SDU4 ............................................................................................ 2-2

2.2.2 Multi-Voltage SDU4 ...................................................................................... 2-3

2.3 Audio Connections ....................................................................................................... 2-3

2.3.1 External Facilities Connector (J503) ........................................................... 2-4

2.4 Set-Up Options ............................................................................................................... 2-4

Center Speaker Switch ............................................................................................. 2-5

Wake-Up Mode Selection ....................................................................................... 2-6

External Master Level Control Switch ................................................................. 2-6

Surround Delay Setting on the Cat No 150......................................................... 2-6

2.5 Input Level Setting......................................................................................................... 2-7

2.6 Output Level Setting ..................................................................................................... 2-8

Output Level Adjustments..................................................................................... 2-9

Master Level Control ............................................................................................... 2-9

SECTION 3–OPERATION...................................................................................................... 3-1

3.1 Operating Modes and Applications........................................................................... 3-1

Mono ........................................................................................................................... 3-1

Stereo........................................................................................................................... 3-1

Dolby Surround ........................................................................................................ 3-1

3.2 Detailed Applications .................................................................................................... 3-1

Broadcast .................................................................................................................... 3-1

Music Recording For Dolby Stereo Films ........................................................... 3-3

Surround Productions ............................................................................................. 3-3

SECTION 4–BLOCK DIAGRAM.......................................................................................... 4-1

1-1

MAIN

SECTION 1

INTRODUCTION

1.1 The SDU4

The Dolby SDU4 is designed for reference monitoring of Dolby encoded film formats or Dolby Surround program material in broadcast, audio-forvideo, and music recording applications. The unit contains a reference 2:4 matrix decoder, like that used in the Dolby monitoring equipment found in film production centers. The 2:4 decoder takes a two-track matrix encoded signal as its input and generates four output signals (Left, Center, Right and Surround). The SDU4 is designed for monitoring rooms where the electroacoustical response conforms to international standards for wide-range audio monitoring. The input program material can originate from any twochannel, reasonably phase-stable source, such as video tape, video disk, motion picture film, or stereo broadcast.

Broadcast applications include evaluation of air-masters of program material originally recorded for theatrical Dolby release. Using the SDU4, the engineer can check for compatibility in mono, conventional stereo, or in a fully decoded surround playback. Music studios will find the SDU4 invaluable when monitoring material intended for integration into Dolby film soundtracks as it provides accurate reproduction of two-channel material in its final dimensional perspective. The SDU4 can also derive a center output signal for monitoring the mono compatibility of conventionally produced stereo material.

An internal calibrate mode, using channel-sequenced pink noise, allows easy verification of monitor levels and equalization. Internal logic allows the correct reproduction of program material either with or without a center loudspeaker. Other features include extended monitor functions, balanced inputs and outputs at professional levels, monitor level control, remote control of all functions and external interface capability.

The SDU4 is designed for use with a Dolby Surround encoder, the SEU4. A first step in equipping a post-production facility for future surround productions should be the installation of the SDU4 and the establishment of a correct monitoring environment.

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1.2 Specifications

Layout:

Rack-mount unit incorporating a professional surround decoder module, interface circuitry, and power supply.

Signal Connections: (on rear panel)

Lt (Left Total) and Rt (Right Total) XLR inputs for two-channel encoded signal; Left, Center, Right, and Surround XLR outputs. Additionally, Lt, Rt, and Left, Center, Right, and Surround monitor points are provided at a 25 pin female D connector.

Front Panel Controls and Indicators:

One toggle switch and three push-button switches control system operating modes and internal test signals. A single rotary knob controls four-channel master level. Screwdriver adjustable controls recessed behind panel for adjustment of input and output levels. LED meters indicate Lt and Rt input level. Signal present LEDs indicate Left, Center, Right, and Surround decoder outputs.

Input Circuit: (0 dBr=0.775 V rms)

Two balanced floating transformerless inputs. Input gain adjustment will accommodate a range of 300 mV (–8.2 dBr) to 2 V rms (+8.2 dBr). Input impedance is greater than 10 k ohms. Maximum common mode voltage 4 V rms, 5.8 V peak.

Output Circuit:

Four balanced floating transformerless outputs. Output gain adjustment will accommodate a range of 250 mV (–9.8 dBr) to 2.5 V (+10.2dBr) at the normal master level control setting. Output impedance 25 ohms.

Maximum output voltage +26 dBr into balanced 600 ohm load, less into lower impedances. Maximum output +20dBr into unbalanced 600 ohm load.

Operating Modes:

Dolby Surround, conventional stereo, and mono modes, selected by front panel pushbutton or remote control.

Pink Noise Calibration Function:

Pink noise from the SDU4’s internal generator can be sent to the outputs in several ways. Noise can be automatically cycled between Left, Center, Right, Surround, remaining for 3 seconds at each output (LCRS sequence); or cycled between Center and Surround remaining for 3 seconds per output (CSCS sequence); or to any desired channel under manual control. The system should be adjusted so this signal produces a sound pressure level (SPL) of 85dBc at the desired monitoring position.

Center Speaker In/Out:

Selected by an internal switch. Used to match either theater-style systems with three front channels or smaller systems with two front loudspeakers. The latter mode routes spatially decoded signals from the surround decoder as follows: left decoder output to Left main output; right decoder output to Right main output; center decoder output split to Left and Right main outputs at a reduced level; surround decoder output to Surround main output.

Monitor Outputs:

Single-ended monitor outputs are provided for Lt and Rt and for L, C, R, and S signals. Dolby level is 500mV (–3.8dBr) at these outputs. Output impedance is 200 ohms or less, and these outputs can drive loads greater than 10 k ohms.

Overall Frequency Response:

20Hz-20 kHz ± l dB (L, C, and R) 100Hz-7 kHz ± 3 dB (surround output)

S/N Ratio: (referenced to Dolby level)

Greater than 80 dB (Left, Center, Right), CCIR/ARM weighted. Greater than 70dB (Surround), CCIR/ARM weighted. (Master level control at normal setting.)

Distortion:

Total Harmonic Distortion (THD) at the main balanced outputs will not exceed 0.25% into balanced loads 600 ohms or greater at any output level up to 12.5 V rms at any master level control setting.

THD at Dolby level at 1kHz with input and output adjusted for +4dBr, 0.1% typical.

Ambient Operating Temperature:

Up to 40 degrees C.

Finish:

Bottom tray and cover clear alodine. Front panel black with white lettering.

Size:

1 Rack Unit 43 mm (1.75") high, 260 mm (10.25") deep behind mounting surface; maximum projection in front of mounting surface 22 mm (0.875").

Weight:

5 kg (11 lb.).

Power Requirements:

The SDU4 consumes about 20 watts and is designed for operation from a centrally switched power source. 230 V version: 198264 V ac, 50/60 Hz, uses one 20 mm T250 mA fuse. Multi-voltage version: 85-132 V ac, 50/60 Hz, uses one 1.25" 500 mA slow-blow fuse, or 187-264 V ac, 50/60 Hz, uses one 20mm T250 mA fuse.

Specifications subject to change without notice.

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1.3 Regulatory Notices

Troubleshooting must be performed by trained technicians. Do not attempt to service the unit unless you are qualified to do so.

WARNING: Check that the units have been set to the correct supply voltage and that the correct fuses have been installed. To reduce the risk of fire, replace the fuses only with the same type and rating. Do not use a groundlifting adaptor and never cut the ground pin on the three-prong power plug.

Connections for United Kingdom:

WARNING: THIS APPARATUS MUST BE EARTHED.

As the colours of the cores in the mains lead may not correspond with the coloured markings identifying the terminals in your plug, proceed as follows:

• The core which is coloured green and yellow must be connected to the terminal in

the plug which is marked with the letter E or by the earth symbol , or coloured green or green and yellow.

• The core which is coloured blue must be connected to the terminal which is marked

with the letter N or coloured black.

• The core which is coloured brown must be connected to the terminal which is

marked with the letter L or coloured red.

EUROPEAN EMC

The 230V unit complies with the EMC requirements of EN 50081-1, EN 50082-1, prEN 55103-1 and -2 when installed in an E2 environment in accordance with this manual.

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