Dolby Laboratories CP65 manual Surround Equalization Alignment Cat. No

Page 55

5-32

B-Chain Alignment Procedures

e. Surround Equalization Alignment (Cat. No. 441)

5-33

B-Chain Alignment Procedures

e. Surround Equalization Alignment (Cat. No. 441)

Step

No.

1

2

3

Re

S

Cat. No.

242

mono eq

mono

gain L non-sync

R

L

signal C present R

Ls

gnd

L

C

test points R

Ls

L

C

gain

R

Ls

Action

Indication

RIGHT

OFF

	04	Dolby Stereo
	04	A-type
		A-type

MONO SURROUND STEREO SURROUND

88 dBC						85 dBC
F
OF						30
0		0	0		0	30
8	7	0	0	50	4
	7		6	50

Dolby

Notes

If your CP65 does not contain the Cat. No. 441 Surround Equalizer and Subwoofer Card, skip this paragraph and go directly to page 5-42, Adjustment of Surround Delay. The CP65 will function without the Cat. No. 441 card, but the surround frequency response cannot be equalized.

The surround equalizer on the Cat. No. 441 card consists of:

•A parametric mid-band section with variable cut, bandwidth, and center frequency.

•Shelving type Bass and Treble controls.

All connections established in the previous procedure still apply to the surround equalization alignment. Confirm that the microphone is in the position defined on page 5.6. Ensure that format 04 is selected.

Note: The Cat. No. 441 can be configured for either Mono or Stereo surround operation using link J3 ( See page 2-5 for details). If Mono operation is selected then an identical signal will be fed to both Ls and Rs outputs in all formats. If only one power amplifier is to be used for the surround channel then the Ls should be used. If more than one surround amplifier is to be used, both outputs may be used to feed, for example, balcony and ground floor. The separate level controls and equalizers may then be used to compensate for differences caused by the different acoustic environments of the two areas. If stereo operation is selected a stereo surround signal will be fed to the surround channels when format 10, Dolby Stereo SR• D is selected.

If the surround speakers are wired for stereo operation or both surround outputs are in use switch off (or disconnect the input to) the right surround amplifier or amplifiers.

Turn on the S switch on the Cat. No. 85C pink noise generator. Be sure that format 04 is selected.

Adjust the Ls ( left surround) gain control on the Cat. No. 242 B-Chain card for a sound pressure level of approximately 85 dBC in the theatre. If only one surround output is used set the level to 88 dBC.

Image 55

Contents Model CP65 Cinema Processor Dolby Laboratories Inc Headquarters Table of Contents Section Reference Block Diagrams Introduction Page Section Equipment Required Jiffy Test Film Cat. No 2 Listen . . . Film Cat. No Smpte Buzz Track Stereo Optical Surround Level Cat. NoSection Initial SET-UP and Installation Voltage Acceptable Setting Voltage Range Fuse Type Next, check the jumpers in the following locations Cat. No , B-Chain Card Cat. No , Power Supply ModuleJ2 NON-SYNC Cat. No , Control Logic CardStandard CP65 or CP65A CP65 BackplaneCP65-300 High Low Subwoofer subwoofer Output output These Modules are Necessary for Bypass Operation Channel Decoder Slot Card Function Cat. NoTwo-channel Noise Reduction ModuleContains a semi-regulated power supply with International Voltage Setting Fuse TypeIEC Notices Room lighting dimmer controls SCR-TYPE HUM ProblemsPage Aligning the B-Chain Section AN Overview of the Alignment ProcedurePage Page Section Chain Alignment Action Indication Preliminary ProceduresLamp Voltage Optical Preamplifier Adjustments Chain Alignment Procedures Optical Preamplifier Adjustments 222 CAT. no Test Film Oscilloscope Traces Repeat Repeat 1 → CAT noMagnetic Preamplifier Adjustments Magnetic Alignment 100mV Section Chain Alignment Bypass Setting Room EqualizationLoudspeakers and Crossovers General AmplifiersOff Chain Alignment ProceduresAction RepeatChain Alignment Procedures Setting Room Equalization Do not adjust Paul 14 → 21 R 14 → Setting Room Equalization b. Adjusting L,C,R Gain79 dBC Setting Mono GainChain Alignment Procedures Subwoofer Alignment Cat. No 85 dBC 90 dBCStep No FromSelect format 04 Dolby Stereo A-Type 441 Same ASSurround Equalization Alignment Cat. No Cat. No 441 Surround Equalization Alignment Cat. No NotesDesired 88 dBC Bypass Thumbwheel Switch Adjustment of Surround DelayMsec Setting Xx dBC Chain Alignment Procedures Adjustment of Bypass GainXx dBC -3 dB Yy dBC FromPress the format 60 non sync switch Adjustment of Non-sync GainAuto Freq Repeat page 5-20 Step Adjustment of Mono Gain and Equalization NotesPress the format 04 Dolby Stereo A-type switch Chain Alignment Procedures Final ChecksSection Reference Diagrams Cat. No Dual Noise Reduction Module Inputs Cat. No Optical Bass Extension and Surround Equalizer Card Cat. No B-Chain Facilities Card Cat. No Power Supply Card Cat. No Transformer Module Inputs Cat. No Control Logic Card 15V +12B Cat. No +24V +15V+15M Appendix a Checking Phasing of Speakers Appendix B Effect of Changes in Slit Height on Slit Losses Operation Appendix C CP65M Mono InstructionsCat. No a Circuit Description Schematic Cat. No a Terminal Block TB3 Appendix D Backplane Connections ListConnector J18