Dolby
®
Model CP650 Installation Manual
B-Chain Alignment
4-26
>Optical Subwoofer
Optical Subwoofer
Optical Subwoofer
Optical Subwoofer
Level: xx
Polarity: Normal
Center Noise: Off
Optical Subwoofer
>Level
>Level
>Level
>Level: xx
Polarity: Normal
Center Noise: off
Optical Subwoofer
Bandwidth
> 50 Hz
Saving Changes.....
...
Note
: If pink noise is not being generated, this indicates that the status of the digital
input has changed. If you are using the digital input on the CP650, either disconnect
or power down the device attached the digital input during level setting. A change in
the digital input bitstream will cause the CP650 to mute the pink noise during level
setting.
Optical Subwoofer Bandwidth
This menu item sets upper frequency limit of the subwoofer channel to either 50 or
100 Hz. The recommended setting depends on the type of screen speakers in your
cinema. If you have direct radiator type screen speakers, set the bandwidth to 50 Hz.
If you have the older horn-loaded type of screen speakers (such as Altec A-4), set the
bandwidth to 100 Hz.
50 Hz / 100 Hz
Press the left menu button once to move the
display one menu step to the
Optical Subwoofer
Bandwidth
.
Rotate the front-panel knob to select the desired
bandwidth.
OK
Press the right-hand
OK
button to save the
selection.
Optical Subwoofer Channel Level
menu
OK
Press the left menu button once to move the
display one menu step to the
Optical Subwoofer
Level
setup menu. Pink noise is now present on
the subwoofer channel only.
Note:
The RTA oscilloscope level reference line displays 10 dB
lower for this adjustment and the pink-noise generator
bandwidth is 50 Hz for the optical subwoofer setup. If the
reference line does not appear, the calibration step may have
failed or was not performed. Repeat the steps in Section 4.4.
Rotate the front-panel knob to move the average
level of the displayed pink noise up or down to the
meet the reference line.
