Installation manual

Dolby
®
Model CP650 Installation Manual B-Chain Alignment
4-9
4.6 Crossover Setup (CP650 with Cat. No. 791)
If your CP650 is not equipped with a Cat. No. 791 Crossover Board, please skip this
section.
Two jumpers, located on the Cat. No. 772A board, must be set to “yes” when a
Cat. No. 791 Crossover Card is installed. CP650s shipped with a Cat. No. 791 board
have the correct jumper setting. See Section 9.3.2 for instructions on gaining access to
the jumpers.
Cat. No. 772A
Cat. No. 791 Crossover Board Present?
Jumpers
C DOLBY LABORATORIES INC. MADE IN THE U.S.A.
YES
YES
J2
J1
MIC LEVEL
HF
MAIN
BYPASS LEVELS
NO
NO
Figure 4–2 Cat. No. 772A Board Jumpers for Cat. No. 791 Crossover
The Cat. No. 791 Crossover Card contains a circuit in each high-frequency output
channel (Left high, Right high, and Center high) to boost high frequencies. This
allows the outputs to overcome the loss caused by placing the high-frequency drivers
behind a perforated theatre screen. The circuit adds a maximum of 8 dB boost starting
at approximately 6 kHz. This boost, combined with the bulk treble and equalization
adjustments, provides enough high-frequency gain to suit most applications.
Since not all applications require this boost, jumpers are provided on the card to
enable or disable it. The jumpers are set to disable at the factory. See Section 9.3.2
for instructions on gaining access to the jumpers.
DISABLE
Cat. No. 791
Screen Loss
Filter Jumpers
ENABLE
CENTER
J3
J5
RIGHT
J2
LEFT
Figure 4–3 Cat. No. 791 Board Jumpers for Screen Loss HF Boost