Installation manual

Dolby
®
Model CP650 Installation Manual B-Chain Alignment
4-21
1
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0kH
z
C
±x.x
dB
-_ _---_
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Discarding Changes..
...
=
+ =
= Flat
= EQ Assist
™
The 27-band RTA now displays on the
oscilloscope.
1 kHz is the default start frequency band selected.
A small marker on the scope trace shows the
frequency band selected. Turn the front-panel
knob (with no button pressed) to select the active
band. The CP650 screen cursor (line) blinks to
indicate which band is active.
When the front-panel knob is rotated to select
frequencies at the far left (or right) side of the
LCD screen, the displayed bands will “scroll” left
or right to show the low- or high-frequency bands.
Press and hold the middle menu button while
moving the front-panel knob to adjust the level of
the selected band. Perform fine adjustment of each
band adjusting the response to be as close as
possible to the standard curve displayed on the
scope.
All of the equalizer bands interact with each other.
You should not start at the low-frequency end of
the response curve and merely work your way to
the high-frequency end. As each band is adjusted,
the response of adjacent bands is affected. Start at
the center frequencies. The desired curve is a flat
frequency response up to 2 kHz, falling at 3 dB
per octave to 8 kHz (1 dB per third-octave band).
If modern woofer systems (vented-box direct
radiator enclosures) are installed in the theatre,
moderate bass equalization may be used down to
40 Hz. Once an adjustment seems OK, work on
the frequencies on either side of it. You may find
that a cut at one frequency is followed by a slight
boost at adjacent frequencies.
Shortcuts:
Spin the front-panel knob counterclockwise
(more than 100 steps) to set the equalization to
flat (no boost, no cut).
Spin the front-panel knob clockwise (more
than 100 steps) to activate the EQ Assist
TM
feature. See the description at the end of this
section.
Caution: Do not press the left menu
change button unless you wish to reset
your changes. All settings would be
lost!