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GLOSSARY
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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.
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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.
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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.
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Dolby Digital
Dolby Digital consists of a total of five channels: three front
channels and two rear channels, 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 quality 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.
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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 front 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.
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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 front speaker 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 famous 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 and Dolby Digital, 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.
APPENDIX
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