Specifications

Audio Technology Reference A-1
En
AAudio Technology Reference
This chapter describes and defines the various technologies used in your Creative Inspire 5.1
Digital 5500.
Dolby Digital
Dolby Digital (also referred to as AC-3) delivers five discrete full-range channels (left, center,
right, left surround and right surround) plus a separate Low Frequency Effects (LFE)
channel.Many soundtracks on the latest generation laser discs, DVDs and High Definition
Television (HDTV), are encoded with Dolby Digital technology. When a 5.1-channel Dolby
Digital program source is playing, such as from a DVD player or game console, the Dolby
Digital indicator light lights up automatically.
Note: Not all media in a DVD will be 5.1-channel encoded. On many DVDs, only the main
movie program will be available in 5.1-channel sound. Other supporting chapters (like a
“Director’s Commentary” section) may be in stereo or mono. For these programs, the Dolby
Digital indicator may not light up, even though the sound will be properly reproduced by the
Creative Inspire 5.1 Digital 5500.
Dolby Pro Logic
Dolby Surround is an earlier surround sound standard that is decoded with a Pro Logic
processor. The Pro Logic steering circuitry derives separate center and rear channels from
encoded stereo program sources.
Pro Logic processing provides a convincing movie soundfield when the material is specifically
encoded for Dolby Surround. Most older stereo movie soundtracks will only be encoded for
Dolby Surround, even though the program source may be a DVD’s digital output. Most DVDs
containing Dolby Surround program material will cause both the Dolby Digital and Dolby Pro
Logic lights to illuminate. Creative Inspire 5.1 Digital 5500 will decode these digitally
transferred Dolby Surround programs through the digital Pro Logic decoder automatically.
CD-ROMs and CDs with Dolby Surround encoding will feature the Dolby Surround logo at the
beginning of the program or on the packaging.
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