Operation
To listen to a program in traditional two-
channel stereo, with only the front left
and right speakers plus the subwoofer, if
installed, press the
Stereo
button
x
on the remote or the
Surround Off
button
Ô
on the front panel.
Dolby Digital
Dolby Digital (also known as AC-3) is the
latest advancement in surround sound
technology, delivering up to five full-
range surround channels (left, center,
right, left surround and right surround)
plus a special dedicated Low-Frequency
Effects (LFE) channel. This represents a
major advancement over traditional
analog surround in that each surround
channel is fully discrete and capable of
full bandwidth reproduction. Dolby
Digital is available on DVD and LV discs,
and it will be a part of the new high-
definition television (HDTV) system
when digital broadcasting begins in
1998. Dolby Digital for the home is based
on the same system used to deliver digital
audio soundtracks in movie theaters,
enabling true cinema reproduction in
your home.
To utilize the Dolby Digital mode you
must have a digital source properly
connected to the AVR55. The RF digital
output of a laser disc player should be
connected to the
AC-3 RF
jack
g
on the
rear panel. Note that this jack is for use
only
with the AC-3 RF output from an LV
player and should not be connected to
any other audio, video or digital device.
Digital datastream outputs from DVD
players, HDTV receivers and CD players
should be connected to the
AC-3/PCM
Optical
or
Coaxial
inputs
¶ f
on the
rear panel. In order to provide a backup
signal and a source for recording, the
analog outputs provided on digital source
equipment should also be connected to
their appropriate rear panel inputs
(e.g., connect the analog stereo audio
output from a DVD to the
DVD
inputs
‹
on the rear panel when you connect the
digital outputs).
Dolby Digital sources must be used in
conjunction with one of the video related
inputs: DVD, TV, Vid 1 or Vid 2. First select
one of these sources so that the video
appears at the unit’s output before choos-
ing digital audio. Next, press the
Digital
Input
button
ı h
that corresponds
to the type of digital input used. An LED
will light above the data type selected,
and a message will scroll across the
Information Display
F
to confirm
your choice.
Finally, press the
AC-3/Dolby Digital
button
z Û
to select Dolby Digital.
The mode name will briefly scroll
in the
Information Display
F
,
and the
Dolby Digital
indicator
B
will illuminate.
Night Mode
A special feature of Dolby Digital is the
Night mode, which enables AC-3 input
sources to be played back with their full
range while reducing the minimum peak
level by
1/4
to
1/3
. This prevents abruptly
loud transitions from causing distur-
bances without reducing the impact of
the digital source. The Night mode is
available only when AC-3 signals with
special data are being played.
To engage the Night mode, press the
Night
button
ˆ f
and note that the
indicator will illuminate above the
Night
button on the front panel.
IMPORTANT NOTES ON
DOLBY DIGITAL PLAYBACK:
1. The AVR55 will decode digital audio
sources with a sampling frequency of
32kHz, 44.1kHz and 48kHz. Although
this will enable it to decode virtually all
DVD movies and HDTV sources, it is pos-
sible that some digital sources may not
be compatible with the AVR55.
2. The AVR55 will automatically detect
most Dolby Digital sources. It is possible,
however, that future source equipment
that could not be anticipated at this time,
may require manual surround mode
selection or analog playback.
3. Note that not all programs recorded in
Dolby Digital contain full 5.1 channel
audio. Consult the program guide that
accompanies the DVD or Laser Disc to
determine which type of audio has been
recorded on the disc. The AVR55 will
automatically sense the type of digital
surround encoding used on an AC-3
program source and adjust to
accommodate it.
4. When a Dolby Digital source is
playing, you may not select one of the
analog surround modes.
5. It is not possible to record the output
of a Dolby Digital program.
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AVR55 120 volt Rev (c) 10/1/97
