Sound Field Operations
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What’s Dolby Surround and Dolby Pro Logic Surround?
Dolby Surround is a system that decodes the extra channels of Dolby
Surround encoded sound tracks on movie videos and TV programs, and
produces sound effects and echoes that make the action seem to envelop
you.
Dolby Pro Logic Surround is a more advanced system developed after
Dolby Surround. The sound image is improved by using four separate
channels: off-screen audio effects, on-screen dialogue, left-to-right
panning, and music. These channels manipulate the sound and enhance
the action as it happens on the screen.
The unit offers PROLOGIC mode for these systems as one of the sound
fields. You can tell if a video tape or laser disc uses Dolby Surround or
Dolby Pro Logic Surround encoded software by looking at the
packaging. (Some video tapes and laser discs may use Dolby Surround
even if it’s not indicated on the package.)
What’s surround sound?
Surround sound consists of three elements, direct sound, early reflected
sound (early reflections), and reverberated sound (reverberation). The
acoustics of the venue affect the way these three sound elements are
heard.
The unit combines the three sound elements in such a way that you can
actually feel the size and type of a particular venue such as a concert
hall. The unit also varies the combination of the sound elements to offer
you a variety of sound fields (THEATER, MONO MOVIE, HALL,
STADIUM, and GAME).
The three sound elements in an actual concert hall
Transition of sound from rear speakers
Taking advantage of the
sound fields
(continued)
Early reflections
Reverberation
Direct sound
Level
Early
reflections Reverberation
Direct sound
Early reflections time
Time
