ADP 303 (serv.man3) - Harman Kardon Audio User Guide / Operation Manual. Page 3

Introduction and Safety Information

The carton and shipping materials used
to protect your new ADP303 during
shipment were specially designed to
cushion it from shock and vibration. We
suggest that you save the carton and
packing materials for use in shipping if
you move or should the unit ever need
repair.

To minimize the size of the carton in
storage, you may wish to flatten it. This
is done by carefully slitting the tape
seams on the bottom and collapsing the
carton down to a more two dimensional
appearance. Other cardboard inserts may
be stored in the same manner. Packing
materials that cannot be collapsed
should be saved along with the carton in
a plastic bag. 

If you do not wish to save the packaging
materials, please note that the carton
and other sections of the shipping
protection are recyclable. Please respect
the environment and discard those
materials at a local recycling center.

When positioning your ADP303 in its
final location, make certain that any
shelf or stand is capable of supporting its
weight, and that there is adequate
ventilation on all sides, as well as on the
top and bottom. Do not place CD’s,
record jackets, owner’s manuals, or other
paper on top of, or beneath the unit. This
will block air flow and create a potential
fire hazard. If the unit is to be enclosed
in a cabinet or rack, make certain that
there is adequate air circulation, with a
means provided for hot air to exit, and
for cool air to be brought in.

Dolby Digital, or AC-3 as it is often
referred to, is a totally new generation of
multi-channel digital audio technology.
Using advanced circuit designs and
specially developed compression
techniques, AC-3 delivers significant
advances over previous multi-channel
systems: it delivers noise free, wide
bandwidth sound and it includes six
separate audio channels. 

AC-3 evolves from Dolby Laboratories’
constant research into new ways to
deliver high quality audio for theatrical
motion picture presentation and
transmission via satellite and
telecommunications links. In fact, the
“AC” in AC-3 stands for “Audio Coding,”
the technique used in Dolby Digital for
data compression. 

The ADP303 digital demodulator/
decoder brings that same 5.1 channel
high quality sound that accompanies
many major motion pictures into your
home when used with a compatible laser
disc player, as well as from future Dolby
Digital sources such as DSS, Digital Video
Disc (DVD) and High Definition
Television (HDTV).

For today’s Laser Disc systems the digital
audio signal is recorded as a modulated
RF signal, similar to the signals used for
FM and TV broadcasts. That is why
connections to a laser disc are made
through an “RF” input. New technology
products such as DVD will feature direct
data outputs, and they are connected
directly to the ADP303’s decoding
circuitry, without the need for the
demodulator stage. Both Coaxial and
Optical data inputs are available. 

Traditional “stereo” recordings consist of
two channels, left and right, even though
the original intent of sound engineers
was to have a multitude of channels
available to present a realistic audio
soundfield. Unfortunately, early
recording techniques for vinyl records

and optical movie soundtracks  were
limited to two channels. Dolby Surround
was the technology that broke the two
channel barrier, by placing two
additional channels within the left and
right signals.

Those two additional channels  presented
center channel information, primarily
for movie dialog, and a single, mono
rear channel for effects. The
combination of these two channels with
the existing left and right signals and low
frequency information derived via filters
or an electronic crossover gave home
theater and musical presentations a
realism never before possible.

Dolby Digital takes surround sound to a
new and even higher level. The use of
digital recording techniques enables all
surround channels to be full range,
where the surround channel in older
matrix surround systems is frequency
limited. Dolby Digital also delivers six
separate, discrete channels, including
highly defined left and right surround
channels. With two rear channels instead
of the single, mono channel of Dolby
ProLogic there is a greater feeling of
reality and presence for surround effects
such as “flyovers” of planes and
spaceships. Discrete digital sound also
enables complete separation between the
left front, center, right front, right rear
and left rear channels. The matrix
system used in conventional surround
recordings was often plagued with cross
talk between the channels. That is now
gone with Dolby Digital.

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24093_ADP 303 Eng.  27/02/1998 10:34  Side 3