Manuals / Dolby Laboratories / Home Audio / Stereo Amplifier

Dolby Laboratories CP65 manual bypass, Amplifiers, General, a. Setting Room Equalization, Action

Models: CP65

1 82

Download 82 pages 36.23 Kb

Page 42

bypass

5-6

B-Chain Alignment Procedures

a. Setting Room Equalization

Step	Action	Indication
No.

5

CONT'D

6

7	NORMAL BYPASS	bypass
		bypass

(switch behind panel)

POWER AMP

ON

5-7

B-Chain Alignment Procedures

a. Setting Room Equalization

Notes

•Check that speakers are correctly connected; that the speaker on the left is really connected to the left power amplifier.

Amplifiers

•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.

•Blown fuses.

Some types of power amplifiers operate at very low gain and distortion even if fuses are blown.

•Good air movement through power amplifiers.

General

If air-conditioning noise is audible in the theatre, arrange for lubrication of the motor, fan bearings, adjustment of belts and drives and cleaning of filters to reduce the ambient noise to a minimum.

Set all the gain controls on all power amplifiers to a known repeatable setting, but do not turn amplifiers on. The preferred setting for the 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.

Position calibrated microphones in the theatre. Whenever possible use multiple microphones and a multiplexer.

For a single microphone the recommended position is shown in the diagram — 2/3 of the way from the front speakers to the rear — but off the axis of the center speaker — 5 feet off the floor level — and angled 45 degrees upward toward the screen. Connect the microphone to the RTA.

Open the front door of the CP65 and ensure that the NORMAL/BYPASS switch is in the BYPASS position.

Turn power ON to the power amplifiers.

Image 42

Dolby Laboratories CP65 manual bypass, Amplifiers, General, a. Setting Room Equalization, Action, Indication

Contents

Installation and Alignment Instructions Model CP65 Cinema ProcessorDolby Laboratories Inc Dolby Laboratories Inc U.S. HeadquartersU.K. European Office 100 Potrero Avenue San Francisco, CA TelephoneINTRODUCTION Table of ContentsINITIAL SET-UPAND INSTALLATION EQUIPMENT REQUIREDAPPENDIX C APPENDIX AAPPENDIX B APPENDIX D04 Dolby Stereo A-type 05 Dolby Stereo SR INTRODUCTIONCP65 60 Non-syncPage SECTION EQUIPMENT REQUIRED 1 Dolby Tone and Pink Noise - Cat. No2 1kHz, 100% Modulation, Left/Right - Cat. No 4Stereo Optical Surround Level - Cat. No TEST FILM3SMPTE Buzz Track JIFFYSECTION INITIAL SET-UPAND INSTALLATION Acceptable SettingVoltage Voltage RangeCat. No Cat. No. 249, Power Supply Module Cat. No. 242, B-ChainCardJ5 J6 J7 J8 Cat. No. 443, Control Logic Card J3 INCP65 Backplane Standard CP65 or CP65AIn a CP65-300when Cat. No. 300 modules are fitted in place of the normal Cat. No. 350 modules J16 and J18 should be rotated so that the words “Format 42” appears the right way up. With J24 in the “NR” position input signals will be A-typedecoded when the Mag/Aux format is selected. With J24 in the “NO NR” position signals pass through the noise reduction modules but the processing will be turned off. If both of these processing options are required frequently an external switch may be connected to J24 CP65-300J1 Optical Bass Extension output level sets the output level range for the subwoofer channel. In the HIGH position J1 is set at the factory for a power amplifier input sensitivity of between 90 mV and 1.23 V. If the power amplifiers used in the installation are very sensitive 10 mV to 100 mV input sensitivity, it may be necessary to set J1 to the LOW position. If you are unsure of the sensitivity of your power amplifiers set J1 to the LOW position initially. If the high output position is required this will be determined during OBE alignment Slot selected projector. Electronic switches selectCard Descriptions Card2 4 Channel Decoder Two-channelNoiseReduction Module 7,8,9Function SlotCard Cat. NoFuse Voltage SettingInternational TypeIMPORTANT SAFETY NOTICE IEC NOTICESGB F D I E S NL IMPORTANT - NOTE DE SECURITEHUM PROBLEMS 3.Room lighting dimmer controls SCR-TYPEModel CP65 With CP65 FADER turned up and format 04 selected SECTION AN OVERVIEW OF THE ALIGNMENT PROCEDURE 1. Aligning the A-Chain2. Aligning the B-Chain and with a broad range of speakers. Accurate equalization requires the use of standardized acoustic measurement procedures Many loudspeakers used in theatres are far from ideal and require boosting of the low- and high-frequencyextremes in order to produce an approximation of the standard reference response curve. Bass and treble controls-centeredon the turnover points of typical loudspeakers-liftthe ends of the spectrum without the need for large amounts of narrow- band boost from the third-octavecontrols in the Cat. No. 64 cards. The third-octavecontrols are used for minor adjustments that are required to smooth the frequency response curve SECTION A-CHAINALIGNMENT Action a. Preliminary Proceduresa. Preliminary Procedures Notes Indicationa. Preliminary Procedures Notes A-ChainAlignment Proceduresa. Preliminary Procedures ActionAction b. Optical Preamplifier Adjustmentsb. Optical Preamplifier Adjustments Notes Indicationb. Optical Preamplifier Adjustments Notes A-ChainAlignment Proceduresb. Optical Preamplifier Adjustments Actionb. Optical Preamplifier Adjustments L L R R L L R RCAT NO b. Optical Preamplifier Adjustments NotesCAT. NO. 97 TEST FILM ActionIndicationn REPEATA-ChainAlignment Procedures OSCILLOSCOPE TRACESRTA DISPLAY b. Optical Preamplifier AdjustmentsA-ChainAlignment Procedures 12 ANDREPEAT b. Optical Preamplifier Adjustmentsb. Optical Preamplifier Adjustments CAT NOFOR PROJECTOR NO. REPEAT 1 → b. Optical Preamplifier Adjustments Notesc. Magnetic Preamplifier Adjustments Magnetic AlignmentA-ChainAlignment Procedures c. Magnetic Preamplifier AdjustmentsMagnetic Alignment SECTION B-CHAINALIGNMENT bypass a. Setting Room Equalizationa. Setting Room Equalization Notes Actiona. Setting Room Equalization Notes Loudspeakers and Crossoversa. Setting Room Equalization ActionGeneral bypassAmplifiers a. Setting Room EqualizationAction B-ChainAlignment Proceduresa. Setting Room Equalization Notes Indicationa. Setting Room Equalization Notes REPEATa. Setting Room Equalization Actiona. Setting Room Equalization Notes B-ChainAlignment Proceduresa. Setting Room Equalization Actiona. Setting Room Equalization Notes Do not adjusta. Setting Room Equalization ActionAction a. Setting Room Equalizationa. Setting Room Equalization Notes IndicationL 14 → 21 R 14 → b. Adjusting L,C,R Gainb.Adjusting L,C,R Gain 22REPEAT79 dBC c. Setting Mono Gainc. Setting Mono Gain Notes ActionB-ChainAlignment Procedures d. Subwoofer Alignment Cat. Nod. Subwoofer Alignment Cat. No. Notes Actiond. Subwoofer Alignment Cat. No 90 dBCB-ChainAlignment Procedures Actiond. Subwoofer Alignment Cat. No FROMd. Subwoofer Alignment Cat. No ActionAction Select format 04 Dolby Stereo A-Typed. Subwoofer Alignment Cat. No REPEATd. Subwoofer Alignment Cat. No SAME ASd. Subwoofer Alignment Cat. No Actione. Surround Equalization Alignment Cat. No Re Se. Surround Equalization Alignment Cat. No Actione. Surround Equalization Alignment Cat. No Actione. Surround Equalization Alignment Cat. No ActionREPEAT 88 dBC e. Surround Equalization Alignment Cat. NoAction Action B-ChainAlignment Procedurese. Surround Equalization Alignment Cat. No Indicationmsec f. Adjustment of Surround DelayThumbwheel Switch Settingxx dBC g. Adjustment of Bypass Gaing. Adjustment of Bypass Gain Notes B-ChainAlignment Proceduresg. Adjustment of Bypass Gain FROM xx dBC -3dB yy dBCB-ChainAlignment Procedures g. Adjustment of Bypass Gain NotesPress the format 60 non sync switch h. Adjustment of Non-syncGainh. Adjustment of Non-syncGain Notes ActionAction h. Adjustment of Non-syncGainh. Adjustment of Non-syncGain Notes Indication5REPEAT PAGE 5-20STEP i. Adjustment of Mono Gain and Equalizationi.Adjustment of Mono Gain and Equalization Notes B-ChainAlignment Proceduresj. Final Checks Press the format 04 Dolby Stereo A-type switchJIFFY TEST FILM j. Final Checks NotesSECTION REFERENCE DIAGRAMS Cat. No. 222 Dual Noise Reduction Module INPUTS OUTPUTSPage Cat. No. 242 B-ChainFacilities Card Cat. No. 249 Power Supply Card Cat. No. 259 Transformer Module INPUTS OUTPUTSCat. No. 443 Control Logic Card +24V CP65 POWER DISTRIBUTION TABLECat. No +15VAPPENDIX A CHECKING PHASING OF SPEAKERS 10,000 Frequency in Hz5,000 20,000APPENDIX C CP65M MONO INSTRUCTIONS 1.Operation2.Cat. No. 327A Circuit Description C.2 Schematic Cat. No. 327A A3C2984 revTerminal Block TB1 APPENDIX D BACKPLANE CONNECTIONS LISTCP65 Backplane Connections Terminal Block TB2D connector J18