AVR 55 (serv.man2) - Harman Kardon Audio User Guide / Operation Manual. Page 24

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 

button 

x

on the remote or the 

button 

Ô

on the front panel.

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 

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 

or 

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 

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 

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

F

to confirm

your choice.

Finally, press the 

button 

z Û

to select Dolby Digital.

The mode name will briefly scroll 
in the 

F

, 

and the 

indicator 

B

will illuminate.

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

button 

ˆ f

and note that the

indicator will illuminate above the

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.

24