Name

By contrast, modern soundtracks use discrete channels of information. That is, each speaker has a distinct signal that is completely independent of every other channel. This approach is clearly more desirable, since it gives the movie-makers more creative control over the quality of your experience. Musicians also prefer discrete formats, since it allows them to place their instruments and voices with greater precision, to create the musical effects they desire.

There are many multi-channel formats available. Table1, below, identifies

the most common multi-channel formats to help you sort out some of the possibilities.

Table 1: Common multichannel modes

Name	# Chs	Matrix/Discrete		Comments
analog stereo	2	Discrete	Found on almost all sources, including
			tape decks, tuners, and CD players.
analog multi-	6-8	Discrete	A multi-channel analog input used
channel input			mostly for SACD & DVD-Audio.
Dolby Surround	4	Matrix	The	original matrix	decoding system
Pro Logic			designed to squeeze four channels into
			two and then retrieve them.
Dolby Pro	Up to 5.1	Matrix	An improvement of Dolby’s original
Logic II			Pro Logic matrix decoder, Dolby PLII
			is designed for 5.1 surround systems.
Dolby Pro	Up to 7.1	Matrix	An improvement of Dolby PLII, this
Logic IIx			version uses the 2ch or 5.1channel
			source audio to create as many as 7.1
			channels (depending on speaker setup)
			of surround sound.
Dolby Digital	1.0-5.1	Discrete	The	most common	modern digital
(formerly AC-3)			source, used in HDTV, DVD, etc.
Dolby	6.1	Discrete	A 7th channel of discrete information
Digital EX			was recorded during filming and
			is encoded into the media. This
			information is used to create a single
			rear center, or two mono rear centers
			depending on the speaker setup (6.1
			or 7.1).
DTS	1.0-5.1	Discrete	Similar to Dolby Digital in practice,
			though it uses a different technology.
DTS-ES Matrix	6.1	Mostly Discrete	The center rear channel is a matrix
			channel encoded into the left and
			right surround channels. The
			processor reads flags and “unfolds”
			the center rear channel information;
			all other channels are discrete.
DTS-ES Discrete	6.1	Discrete	All 6.1 channels are discrete

DTS Neo:6	5-6	Matrix	Designed for the playback of film or
			music sources and can derive 5 or 6
			channels with surround and/or rear
			speakers

Comments

source, used in HDTV, DVD, etc.

DTS

DTS-ES Matrix