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APPENDIX
APPENDIX
■ Encode/Decode
When a signal or other information is processed,
compressed and digitized, this is called encoding. Encoding
can be used to record an extremely large amount of
information on a single CD or DVD.
An encoded signal cannot be listened to directly. It must be
returned to its original state (i.e. audible sound) and this is
called decoding.
■ Sound field
Not all sound travels from the sound source directly into the
human ear, but instead reflects off of walls, ceilings and
other objects to arrive at the ear slightly delayed (early
reflection). It may also reflect repeatedly in a complicated
manner before reaching the ear (subsequent reverberation).
A human is able to perceive the size and shape of a location
based on the various sounds heard in this way. The specific
acoustic space of a particular building is called a sound
field.
■ Dolby Surround
In movie theaters and in live theaters, the spectators are
surrounded by many speakers and sound effects geared to
each scene are used to make sound move from front to back
and right to left. This gives the sound a three dimensional
feel that surrounds the entire body. Dolby Surround is used
to implement this realistic effect. Originally, the Dolby
Surround system consisted of a total of four channels: two
front channels (right and left), one center channel, and one
rear channel. Later, two-channel stereo compatibility was
added to for broadcast and video media used in the home.
The ability to easily set up a home AV system capable of
stereo reproduction is one of the biggest features of Dolby
Surround.
■ Dolby Digital
Dolby Digital consists of a total of five channels: three front
channels (left, center and right) and two rear channels (right
and left), plus a distinct LFE channel for low frequency
effect. It is therefore commonly referred to as a 5.1 channel
system. Using digital compression technology for all 5.1
channels, Dolby Digital can be used for completely
independent audio reproduction. Dolby Digital offers
superior sound separation between each channels and a
more three dimensional surround effect in comparison to the
older Dolby Surround, which mixes four channels (three
front and one rear) into two-channel stereo and separates
them using a matrix circuit.
■ DTS (Digital Theater Systems)
Digital Surround
DTS was developed to replace the analog soundtracks of
movies with six discrete channels of digital soundtracks,
and it is now installed in many theaters around the world.
The DTS digital playback system changed the way we
experienced movies in theaters with six discrete channels of
superb digital audio.
GLOSSARY
DTS technology, through intense research and development
has made it possible to deliver similar encode/decode
discrete technology to home audio surround-sound
entertainment.
DTS Digital Surround is an encode/decode system which
delivers six channels of master-quality, 20-bit audio;
technically, it is 5.1 channels, which means 5 full-range
(left, center, right and two surround) channels, plus a
subwoofer (LFE) channel (as “0.1”). It is compatible with
the 5.1 speaker configurations that are currently available
for home theater systems.
■ Virtual surround
We basically perceive the direction from which sounds
come to us based on the difference in time they reach the
right and left ears and differences in sound level. Virtual
technology is based on this property of the human ear. A
DSP (digital sound field processor — a form of digital
signal processing) and right and left main speakers are used
so that the listener feels like he or she is hearing sounds that
come from virtual speakers located in directions other than
just the two physical speakers. This allows the listener to
experience surround effects as if rear speakers were present
as in a five-speaker system.
■ YAMAHA DSP (Digital Sound Field
Processor)
YAMAHA technicians traveled to world famous concert
halls, opera houses and other locations just to measure
acoustical information such as the direction, intensity, band
characteristics, and delay time of reflected sounds. This
wealth of information was then put on a ROM.
Using a built-in YAMAHA DSP (digital sound field
processor) to create sound fields, this unit allows you to
freely select various sound field programs created from this
actual acoustical data so that you can reproduce the sound
field of concert halls and live houses right in your listening
room.
Movie makers design sounds for a movie so that the sound
and screen become one. Dialog is positioned right on the
screen, sound effects behind the screen, music behind that,
and surround effects wrap around the audience.
CINEMA DSP is a program for use in AV reproduction that
has evolved from YAMAHA DSP. Fusing the movie sound
decoders, Dolby Pro Logic, Dolby Digital and DTS, with
YAMAHA DSP, allows you to reproduce the type of
surround sound field of the quality found on a dubbing stage
designed to optimize movie surround conditions. (A
dubbing stage is the final mix used to complete the final
sound design for a movie.)
By adding YAMAHA DSP processing to both the right and
left front channels and the center channel, the CINEMA
DSP program wraps the audience in a surround sound field
that not only makes dialog real, but penetrates and
surrounds the screen to give depth to sound effects and
music as well as a smooth sense of movement to sound
sources.