Dolby Laboratories CP65 manual 88 dBC

5-38

B-Chain Alignment Procedures

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

Step

Action

Indication

No.

10

MONO SURROUND

STEREO SURROUND

Cat. No.

88 dBC

85 dBC

242

mono eq

mono

gain

non-syncL

R

OFF

0

80

0

60

50

0

3

7

4

L

signal

C

present R

Ls

gnd

L

test

C

points

R

Ls

Dolby

L

gain

C

R

Ls

11

RIGHT SURROUND AMP

ON

LEFT SURROUND AMP

OFF

12

Cat. No.

441

85 dBC

signal

present

tp

Subwoofer

on

cut

auto

freq

OFF

0

03

off

80

7

0

0

50

4

Q

6

n-sync

opt gain

surr

mag/dig

gain

gain

treble

Surround

cut

mid

freq

Q

Left

bass

tp

Dolby

treble

Surround

cut

mid

freq

Q

Right

bass

gain

gnd

signal

present

13

REPEAT

3

→ 10

5-39

B-Chain Alignment Procedures

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

Adjust the Ls (Left surround) gain control on the Cat. No. 242 B-Chain card for a sound pressure level of 85 dBC (or 88 dBC if only one surround output is to be used).

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

With the microphone still located at the center of the theatre, adjust the Right Surround gain control on the Cat. No. 441 surround and subwoofer card for a sound pressure level of 85 dBC.

Repeat Steps 3 through 10 using the Right Surround pots on the Cat. No. 441 card. NOTE: When you reach Step 10 remember that the right surround gain control is located on the Cat. No. 441 board.