32
OPERATION
Operation
To listen to a program in traditional two-channel
stereo, using the front left and front right
speakers only (plus the subwoofer, if installed and
configured), press the
Stereo Button
5
until
S U R R O F F
appears in the
Main
Information Display
˜
.
Digital Audio Playback
Digital audio is a major advancement over older
analog surround processing systems such as
Dolby Pro Logic. It delivers five or six discrete
channels: left front, center, right front, left
surround and right surround and with DTS ES
(see below) even surround back (with identical
signals for left and right). Each channel repro-
duces full frequency range (20Hz to 20kHz) and
offers dramatically improved dynamic range and
significant improvements to signal-to-noise
ratios. In addition, digital systems have the
capability to deliver an additional channel that is
specifically devoted to low-frequency infor-
mation. This is the “.1” channel referred to when
you see these systems described as “5.1,” “6.1”
or “7.1”. The bass channel is separate from the
other channels, but since it is intentionally
bandwidth-limited, sound designers have given it
that unique designation.
Dolby Digital
Dolby Digital (originally known as AC-3
®
) is
a standard part of DVD, and is available on
specially encoded LD discs and satellite
broadcasts and it is a part of the new high-
definition television (HDTV) system.
Note that an optional, external RF demodulator
is required to use the AVR 4550 to listen to the
Dolby Digital sound tracks available on laser
discs. Connect the RF output of the LD player to
the demodulator and then connect the digital
output of the demodulator to the
Optical
or
Coaxial
inputs
!$
*Ó
of the AVR 4550.
No demodulator is required for use with DVD
players or DTS-encoded laser discs.
DTS
DTS is another digital audio system that is capa-
ble of delivering 5.1, 6.1 or 7.1 audio. Although
both DTS and Dolby Digital are digital, they use
different methods of encoding the signals, and
thus they require different decoding circuits to
convert the digital signals back to analog.
DTS-encoded sound tracks are available on select
DVD and LD discs, as well as on special audio-
only DTS CDs. You may use any LD, DVD or CD
player equipped with a digital output to play
DTS-encoded special audio-only CDs with the
AVR 4550, but DTS-LDs can be played on LD
players and DTS-DVDs on DVD players only. All
that is required is to connect the player’s digital
output to either the
Optical
or
Coaxial
input on
the rear panel
!$
or front panel
*Ó
.
In order to listen to DVDs encoded with DTS
sound tracks, the DVD player must be compatible
with the DTS signal as indicated by a DTS logo
on the player’s front panel. Note that early DVD
players may not be able to play DTS- encoded
DVDs. This does not indicate a problem with the
AVR 4550, as some players cannot pass the DTS
signal through to the digital outputs. If you are in
doubt as to the capability of your DVD player to
handle DTS DVDs, consult the player’s owner’s
manual.
Please note that some DVD players are shipped
with their output set for Dolby Digital only. To
insure that DTS data is being sent to the AVR,
please check the setup menu system on your
DVD player to make certain that DTS data output
is enabled.
PCM Audio Playback
PCM (Pulse Code Modulation) is the non- com-
pressed digital audio system used for compact
discs, Non-Dolby Digital/DTS Laserdiscs and some
special PCM encoded DVDs. The digital circuits in
the AVR 4550 are capable of high quality digital-
to-analog decoding, and they may be connected
directly to the digital audio output of your
CD/DVD or LD player (LD only for PCM or DTS
programs, for Dolby Digital laser discs an RF
adapter is needed, see ”Dolby Digital” above).
Connections may be made to either the
Optical
or
Coaxial
inputs
!$
on the rear panel or the
front panel
Digital Inputs
*Ó
.
To listen to a PCM digital source, first select the
input for the desired source (e.g., CD) to feed its
video signal (if any) to the TV monitor and to
provide its analog audio signal for recording.
Next press the
Digital Select
button
Û
G
and then use the
⁄
/
¤
buttons
D
on the
remote, or the
Selector
buttons
7$
on the
front panel, until the desired choice appears in the
Lower Display Line
B
, then press the
Set
button
@
F
to confirm the choice.
During PCM playback the unit automatically will
turn to the default surround mode or to the
LOGIC 7
mode but you also may select any
surround mode except Dolby Digital or DTS.
MP3 Audio Playback
The AVR 4550 is one of the few A/V receivers to
provide on-board decoding for the MP3 audio
format used on specific computer audio files and
by portable MP3 players/recorders. In addition,
some new CD and DVD players are capable of
playing back optical discs that are recorded with
MP3, rather than standard CD audio information.
By offering MP3 decoding, the AVR 4550 is able
to deliver more precise conversion of the digital
signals to an analog output, along with the
benefits of listening to MP3 audio through the
AVR 4550’s high current amplifier and the
speakers from your surround system, rather than
the smaller speakers and low powered amplifiers
typically used with computers.
To take advantage of the AVR 4550’s MP3 capa-
bilities, simply connect the digital (SPDIF) output
of a computer sound card able to feed the MP3
format to its digital output, or the digital (SPDIF)
output of MP3 compatible CD or DVD players or
of a portable MP3 player with a digital output to
either the rear panel
Digital Inputs
!$
or
the front panel
Digital Inputs
*Ó
.
NOTES:
• The AVR 4550 is only capable of playing sig-
nals in the MP3 (MPEG 1/Layer 3) format. It is
not compatible with other computer audio
codecs.
• The MP 3 DSP mode found in the new
AVR 4550 requires an MP3 SPDIF stream.
Presently, only a few units provide this but in the
coming generations of motherboards and
operating system updates this will follow, since
SPDIF is the standard for audio & video
hardware.
• The digital audio input signal may be either
optical or coaxial, but the signal must be in the
MP3 SPDIF format. Direct connection of USB or
serial data outputs is not possible, even though
the signals are in the MP3 format. If you have
any questions about the data output format from
your computer or a sound card, check with the
device’s Owner’s Manual or contact the
manufacturer’s technical support area.
• If your computer or sound card’s digital output
is not capable of direct connection to the AVR or
if the output is not capable of delivering MP3
data stream, you may use an optional, external
transcoder, such as those available from Harman
Kardon to convert the USB output of a computer
to a format compatible with the AVR. Contact
your Harman Kardon dealer for additional details.
