Dolby Laboratories CP65 manual Surround Equalization Alignment Cat. No Notes, Cat. No 441

Page 56

5-34

B-Chain Alignment Procedures

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

Step

Action

Indication

No.

3

Cat. No.

441

signal

dB

present

+10

tp

Subwoofer

on

cut

auto

freq

+5

off

Q

n-sync

opt gain

surr

mag/dig

gain

gain

0

treble

Surround

cut

mid

freq

Dolby

–5

Left

Q

bass

tp

–10

treble

Surround

cut

.05

.1

.2

.4

.8

1.6

3.15

6.3

12.5

kHz

mid

freq

Q

Right

bass

gain

gnd

signal

present

4

Cat. No.

441

signal

present

dB

tp

+10

Subwoofer

on

NOTE

cut

freq

auto

Dolby

off

Q

+5

n-sync

opt gain

surr

mag/dig

gain

gain

treble

0

Left Surround

cut

mid

freq

Q

–5

bass

tp

treble

–10

cut

Surround

.05

.1

.2

.4

.8

1.6

3.15

6.3

12.5

kHz

mid

freq

Q

Right

bass

gain

gnd

signal

present

5

Cat. No.

441

signal

present

tp

Subwoofer

on

cut

Dolby

auto

freq

off

Q

n-sync

opt gain

surr

mag/dig

gain

gain

treble

Surround

cut

mid

freq

Q

Left

bass

tp

treble

Surround

cut

mid

freq

Q

Right

bass

gain

gnd

signal

present

5-35

B-Chain Alignment Procedures

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

Adjust the Left Surround bass control on the Cat. No. 441 card for as flat as possible low frequency response on the RTA. Use caution when adjusting the bass control; many surround loudspeaker systems are deficient in their low frequency response. Attempts to boost the output of such system beyond their capabilities simply wastes amplifier power and can result in distortion and possibly damage to the surround loudspeakers.

Adjust the Left Surround treble control to its mid point, so that it provides neither cut nor boost.

Adjust the mid frequency controls as follows: Turn the Cut control fully clockwise (CW). Set the Q and freq controls to their mid positions.

Note the position of the center of the highest frequency peak in the 350 Hz to 3 kHz region on the analyzer screen.

Turn the Cut control fully counterclockwise and note the position of the notch produced by the equalizer.

Image 56

Contents Model CP65 Cinema Processor Dolby Laboratories Inc Headquarters Table of Contents Section Reference Block Diagrams Introduction Page Section Equipment Required Smpte Buzz Track Stereo Optical Surround Level Cat. No Jiffy Test Film Cat. No 2 Listen . . . Film Cat. NoSection Initial SET-UP and Installation Voltage Acceptable Setting Voltage Range Fuse Type Next, check the jumpers in the following locations Cat. No , Power Supply Module Cat. No , B-Chain CardCat. No , Control Logic Card J2 NON-SYNCCP65 Backplane Standard CP65 or CP65ACP65-300 High Low Subwoofer subwoofer Output output These Modules are Necessary for Bypass Operation Slot Card Function Cat. No Two-channel NoiseReduction Module Channel DecoderContains a semi-regulated power supply with Voltage Setting Fuse Type InternationalIEC Notices HUM Problems Room lighting dimmer controls SCR-TYPEPage Section AN Overview of the Alignment Procedure Aligning the B-ChainPage Page Section Chain Alignment Preliminary Procedures Action IndicationLamp Voltage Optical Preamplifier Adjustments Chain Alignment Procedures Optical Preamplifier Adjustments 222 CAT. no Test Film Oscilloscope Traces Repeat CAT no Repeat 1 →Magnetic Preamplifier Adjustments Magnetic Alignment 100mV Section Chain Alignment Setting Room Equalization BypassLoudspeakers and Crossovers Amplifiers GeneralChain Alignment Procedures OffRepeat ActionChain Alignment Procedures Setting Room Equalization Do not adjust Paul Setting Room Equalization b. Adjusting L,C,R Gain 14 → 21 R 14 →Setting Mono Gain 79 dBCChain Alignment Procedures Subwoofer Alignment Cat. No 90 dBC 85 dBCFrom Step NoSelect format 04 Dolby Stereo A-Type Same AS 441Surround Equalization Alignment Cat. No Surround Equalization Alignment Cat. No Notes Cat. No 441Desired 88 dBC Bypass Msec Setting Adjustment of Surround DelayThumbwheel Switch Chain Alignment Procedures Adjustment of Bypass Gain Xx dBCFrom Xx dBC -3 dB Yy dBCAdjustment of Non-sync Gain Press the format 60 non sync switchAuto Freq Adjustment of Mono Gain and Equalization Notes Repeat page 5-20 StepChain Alignment Procedures Final Checks Press the format 04 Dolby Stereo A-type switchSection 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 +15M Cat. No +24V +15V15V +12B Appendix a Checking Phasing of Speakers Appendix B Effect of Changes in Slit Height on Slit Losses Cat. No a Circuit Description Appendix C CP65M Mono InstructionsOperation Schematic Cat. No a Appendix D Backplane Connections List Terminal Block TB3Connector J18