Dolby Laboratories SDU4 manuale d’uso

î î î î Model SDU4 Surround Decoder User's Manual Issue 2 Part No. 91413 MAIN[...]

User's Manual Model SDU4 Surr ound Decoder Dolby Laborator ies Incorpor ated U.S. A. 100 Pot r er o A v enue, San F ranc i sco, CA 94103- 4813 Tel : 415- 558- 0200; Fax : 415-863- 1373; W eb: www. d o l b y . c o m U.K. W ootto n Ba s s ett, Wi l ts hire SN4 8QJ Tel : ( 44) 1793- 842100; Fax : (44) 1793-842101 DISCLA IMER OF WA RRA NTIES : Equ[...]

i T ABLE OF CONTENTS SECTION 1–INTRODUCTION ............................................................................................. 1 -1 1.1 The SDU4 ......................................................................................................................... 1 -1 1.2 Specifications ..............................................[...]

1-1 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-for- video, 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 cen[...]

1-2 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, [...]

1-3 1.3 Regulatory Notices UL 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 [...]

1-4 IMPOR T ANT SAFETY NOTICE This unit complies with the safety standard IEC65. T o ensure safe operation and to guar d against potential shock hazard or risk of fir e, the following must be observed: • Ensure the voltage selector is set to the correct mains voltage for your supply . • Ensure fuses fitted are the correct rating and type as mar[...]

2-1 SECTION 2 INST ALLA TION AND CALIBRA TION 2.1 Monitor Setup Front Loudspeaker Arrangement The SDU4 is designed for monitoring rooms with either two or three front loudspeakers. The choice between using either two or three front loudspeakers depends upon the distance between the Left and Right speakers, (how large the stereo image is) and how th[...]

2-2 Surround Loudspeakers The surround loudspeakers are used to distribute a single channel of sound in a diffuse field behind the viewer. The number of loudspeakers needed, therefore, depends upon the size of the area to be covered. In smaller rooms, such as those used for video production and home surround installations, two loudspeakers generall[...]

2-3 2.2.2 Multi-Voltage SDU4 OPEN THE DOOR SPARE FUSE (UPPER) FUSE ACTIVE FUSE CARRIER (LOWER) FUSE OCTAGONAL PEG ROUND PEG VOLTAGE SELECTOR WHEEL A2F4037 Figure 2.3 Fuse compartment, multi-voltage unit Open the fuse compartment door in the AC mains input connector with a small flat blade screwdriver (see Figure 2.3), and check that the fuse has th[...]

2-4 2.3.1 External Facilities Connector (J503) +24V DC GROUND CHASSIS GROUND SURROUND MONITOR RIGHT MONITOR CENTER MONITOR LEFT MONITOR MONO STEREO DOLBY SURROUND LEFT TOTAL MONITOR RIGHT TOTAL MONITOR REMOTE FADER TOP REMOTE FADER WIPER DC GROUND 20 +15V 19 16 15 18 J503 FEMALE D-CONNECTOR 17 23 7 21 10 9 11 3 4 5 6 12 13 24 2 1 25 14 -15V 22 8 Fi[...]

2-5 controls are on the right-hand module, Cat. No. 344, as shown in Figure 2.5. Figure 2.5 Cat. No. 344 Center Speaker Switch Switch S301 allows the SDU4 to be installed in monitoring rooms that have either two loudspeakers (labeled “center speaker, no”) or three loudspeakers (“yes”). The factory setting is “yes.” While decoding Dolby [...]

2-6 SDU4 OUTPUTS—CENTER LOUDSPEAKER SWITCH SET TO “NO” Mode Left Ri gh t Surround Mono .707 (Lt & Rt) .707 (Lt & Rt) — Stereo L t R t — Dolby Surround L + . 707 ( C) R + .707 (C) S Wake-Up Mode Selection The SDU4 can be set to default to any operating mode when power is first turned on. This is set using the internal jumpers J1/J2[...]

2-7 The delay setting can be estimated by using the following method: 1. Estimate the distance between the primary listening location and the nearest surround loudspeaker, in feet. If the metric system is used, convert the distance from meters to feet by multiplying by three (3). 2. Estimate the distance from the primary listening location to the f[...]

2-8 The SDU4 contains two four element LED calibration indicators for setting of input level. The two input level potentiometers are set so that reference tone from the signal source, representing the studio’s operating level, is equal to the SDU4’s internal operating level. Any level between –8 dBr and +8 dBr can be set to correspond with th[...]

2-9 R C L S OUTPUT LCRS OFF CSCS NOISE SEQUENCE AUTO MANUAL PINK NOISE Figure 2.9 Pink-noise calibrate functions Output Level Adjustments Output potentiometers are provided so that the decoder output level can be matched to the monitor system. Typically, the SDU4 output level is set using the internal pink noise source. The front panel master level[...]

3-1 SECTION 3 OPERA TION 3.1 Operating Modes and Applications The SDU4 has three modes of normal operation: Mono, Stereo and Dolby Surround. Mono The mono mode combines the Lt and Rt input signals into a single channel and routes it to the Center loudspeaker, if the internal switch S301 is in the "yes" position. If the internal switch is [...]

3-2 The matrix format used on Dolby soundtracks is compatible with both monophonic and conventional stereo playback. Many home viewers have purchased Dolby Surround decoding equipment for use during playback of prerecorded videotape or videodisk program material. These consumer grade decoders are being manufactured by the many companies who are lic[...]

3-3 center channel information. This, in effect, will cause the mono-compatible elements of the mix to appear to always come from the center of the picture. On the other hand, the incompatible elements (those that would cancel if the two input channels were summed) would be reproduced around and behind the listener. This spatial effect is useful as[...]

4-1 SECTION 4 BLOCK DIAGRAM PIN 1 4 = CHASSIS 3 = LO 2 = HI 1 = CHASSIS NC NC NC REMOTE RT R S LT L C POWER-ON MODE SELECT DOLBY AUTO MANUAL 11 TO REMOTE FADER 1 SELECT FADER CONTROL VOLTAGE GEN MUTE A 19 FADER LOCAL AND LOGIC SURROUND DOLBY MONO 22 OUTPUT AMP V 18 AMP OUTPUT U 17 P501 2 3 1 CENTER P502 2 3 1 RIGHT AMP OUTPUT T 16 P503 2 3 1 AMP OU[...]