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Dolby Laboratories CP65 manual Repeat, a. Setting Room Equalization, Action

Models: CP65

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REPEAT 11

5-10

B-Chain Alignment Procedures

a. Setting Room Equalization

Step			Action							Indication
No.
12		Cat. No.
12		242
	mono eq
	mono
	gain
	non-syncL
		R								75-80 dBC
		L								75-80 dBC
		L
	signal	C
	present R
		Ls
	gnd
		L
				FF
		C	O						0	30
	test			80		70	60	50	0
	test					70	60	50	4
	points R
		Ls
		L	Dolby
		L
	gain	C
	gain	R
		R
		Ls
13	REPEAT 11		→ 12
		Cat. No.
		242
	mono eq
	mono
	gain									75-80 dBC
	non-syncL
		R
		L
	signal	C
	present R
		Ls
	gnd		FF
	gnd		O	0		0			0	30
				8	7	0	60	50	4
					7		60	50
		L
	test	C
	test
	points	R
		Ls
			Dolby
		L
	gain	C
	gain	R
		R
		Ls
	Cat. No.
		242
	mono eq
	mono									75-80 dBC
	gain
	non-syncL
		R
		L
	signal	C
	present R
	Ls		OFF
	gnd		OFF							0
				80	70		0	50	0	3
				80			0		4
							6
		L
	test	C
	test
	points	R
	Ls		Dolby
	Ls
		L
	gain	C
	gain	R
		R
	Ls

5-11

B-Chain Alignment Procedures

a. Setting Room Equalization

Notes

With a sound pressure level meter located at the position in the theatre used for step 6, adjust the center channel gain on the Cat. No. 242 card until the channel produces a reading of 75-80 dBC. (After room equalization for all channels is set, the sound pressure level will be set to 85 dBC.) The pink noise should be at least 20 dB above the background noise level of the theatre. If a level of 75-80 dBC cannot be obtained, adjust the gain of the amplifiers and and try again. A row of four LEDS, signal present L, C, R and S, is on the front edge of the Cat. No. 242 card. Each LED indicates the presence of signal for the appropriate channel and lights intermittently when pink noise is sent through the system from the Cat. No. 85C or from a film.

Repeat steps 11 and 12 for the left and right channels. Switch on the appropriate pink noise switch on the Cat. No. 85C pink noise generator, one channel at a time.

Compare the response displayed on the real time analyzer (RTA) for each channel (L, C, R). All should show a similar shape. Any large differences indicate faulty or misaligned crossovers or defective speakers. Speaker phasing could also be at fault. See Appendix A.

Image 44

Dolby Laboratories CP65 manual Repeat, Action, a. Setting Room Equalization Notes

Contents

Installation and Alignment Instructions Model CP65 Cinema ProcessorDolby Laboratories Inc U.S. Headquarters U.K. European OfficeDolby Laboratories Inc 100 Potrero Avenue San Francisco, CA TelephoneTable of Contents INITIAL SET-UPAND INSTALLATIONINTRODUCTION EQUIPMENT REQUIREDAPPENDIX A APPENDIX BAPPENDIX C APPENDIX DINTRODUCTION CP6504 Dolby Stereo A-type 05 Dolby Stereo SR 60 Non-syncPage 2 1kHz, 100% Modulation, Left/Right - Cat. No SECTION EQUIPMENT REQUIRED1 Dolby Tone and Pink Noise - Cat. No TEST FILM 3SMPTE Buzz Track4Stereo Optical Surround Level - Cat. No JIFFYSECTION INITIAL SET-UPAND INSTALLATION Setting VoltageAcceptable Voltage RangeCat. No J5 J6 J7 J8 Cat. No. 249, Power Supply ModuleCat. No. 242, B-ChainCard 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 selected projector. Electronic switches select Card DescriptionsSlot CardTwo-channelNoise Reduction Module2 4 Channel Decoder 7,8,9Slot CardFunction Cat. NoVoltage Setting InternationalFuse TypeIEC NOTICES GB F D I E S NLIMPORTANT SAFETY NOTICE IMPORTANT - NOTE DE SECURITEModel CP65 HUM PROBLEMS3.Room lighting dimmer controls SCR-TYPE With CP65 FADER turned up and format 04 selected 2. Aligning the B-Chain SECTION AN OVERVIEW OF THE ALIGNMENT PROCEDURE1. Aligning the A-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 a. Preliminary Procedures a. Preliminary Procedures NotesAction IndicationA-ChainAlignment Procedures a. Preliminary Proceduresa. Preliminary Procedures Notes Actionb. Optical Preamplifier Adjustments b. Optical Preamplifier Adjustments NotesAction IndicationA-ChainAlignment Procedures b. Optical Preamplifier Adjustmentsb. Optical Preamplifier Adjustments Notes ActionL L R R L L R R CAT NOb. Optical Preamplifier Adjustments b. Optical Preamplifier Adjustments NotesAction IndicationnCAT. NO. 97 TEST FILM REPEATOSCILLOSCOPE TRACES RTA DISPLAYA-ChainAlignment Procedures b. Optical Preamplifier Adjustments12 AND REPEATA-ChainAlignment Procedures b. Optical Preamplifier AdjustmentsCAT NO FOR PROJECTOR NO. REPEAT 1 →b. Optical Preamplifier Adjustments b. Optical Preamplifier Adjustments Notesc. Magnetic Preamplifier Adjustments Magnetic AlignmentMagnetic Alignment A-ChainAlignment Proceduresc. Magnetic Preamplifier Adjustments SECTION B-CHAINALIGNMENT a. Setting Room Equalization a. Setting Room Equalization Notesbypass ActionLoudspeakers and Crossovers a. Setting Room Equalizationa. Setting Room Equalization Notes Actionbypass AmplifiersGeneral a. Setting Room EqualizationB-ChainAlignment Procedures a. Setting Room Equalization NotesAction IndicationREPEAT a. Setting Room Equalizationa. Setting Room Equalization Notes ActionB-ChainAlignment Procedures a. Setting Room Equalizationa. Setting Room Equalization Notes ActionDo not adjust a. Setting Room Equalizationa. Setting Room Equalization Notes Actiona. Setting Room Equalization a. Setting Room Equalization NotesAction Indicationb. Adjusting L,C,R Gain b.Adjusting L,C,R GainL 14 → 21 R 14 → 22REPEATc. Setting Mono Gain c. Setting Mono Gain Notes79 dBC Actiond. Subwoofer Alignment Cat. No d. Subwoofer Alignment Cat. No. NotesB-ChainAlignment Procedures Action90 dBC B-ChainAlignment Proceduresd. Subwoofer Alignment Cat. No ActionFROM d. Subwoofer Alignment Cat. Nod. Subwoofer Alignment Cat. No ActionSelect format 04 Dolby Stereo A-Type d. Subwoofer Alignment Cat. NoAction REPEATSAME AS d. Subwoofer Alignment Cat. Nod. Subwoofer Alignment Cat. No ActionRe S e. Surround Equalization Alignment Cat. Noe. Surround Equalization Alignment Cat. No Actione. Surround Equalization Alignment Cat. No ActionREPEAT e. Surround Equalization Alignment Cat. NoAction Action 88 dBCe. Surround Equalization Alignment Cat. No B-ChainAlignment Procedures e. Surround Equalization Alignment Cat. NoAction Indicationf. Adjustment of Surround Delay Thumbwheel Switchmsec Settingg. Adjustment of Bypass Gain g. Adjustment of Bypass Gain Notesxx dBC B-ChainAlignment ProceduresFROM xx dBC -3dB yy dBC B-ChainAlignment Proceduresg. Adjustment of Bypass Gain g. Adjustment of Bypass Gain Notesh. Adjustment of Non-syncGain h. Adjustment of Non-syncGain NotesPress the format 60 non sync switch Actionh. Adjustment of Non-syncGain h. Adjustment of Non-syncGain NotesAction Indicationi. Adjustment of Mono Gain and Equalization i.Adjustment of Mono Gain and Equalization Notes5REPEAT PAGE 5-20STEP B-ChainAlignment ProceduresPress the format 04 Dolby Stereo A-type switch JIFFY TEST FILMj. Final Checks 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 CP65 POWER DISTRIBUTION TABLE Cat. No+24V +15VAPPENDIX A CHECKING PHASING OF SPEAKERS Frequency in Hz 5,00010,000 20,0002.Cat. No. 327A Circuit Description APPENDIX C CP65M MONO INSTRUCTIONS1.Operation C.2 Schematic Cat. No. 327A A3C2984 revAPPENDIX D BACKPLANE CONNECTIONS LIST CP65 Backplane ConnectionsTerminal Block TB1 Terminal Block TB2D connector J18