Audio Design Associates Cinema Reference Mach II PTM-8150 - Manual (Page 77)

Page 76
Multi-Channel Formats
Dolby Digital and Dolby Digital Surround EX
A Dolby Digital bit stream most typically contains a 5.1 channel mix
or upon closer inspection, a 3.2.1.0 mix. To examine this further, the
3 refers to the front three channels (left, center, right), the 2 refers to
the surround channels (left and right), and the 1 or “.1” refers to the
subwoofer (also often called LFE - Low Frequency Effects). While
there are other options for mixing Dolby Digital (older movies that
were never mixed in multi-channel but play off a DVD are often en-
coded in Dolby Digital, as 2.0.0.0 or stereo), most material is avail-
able in a 5.1 format.
Dolby Digital Surround EX is best described as an enhancement to
Dolby Digital. Here a mono signal is embedded into the discrete
surround left and right channels. This signal creates an image in the
back of the room, between the surround left and right channels. If a
film has been encoded in Dolby Digital Surround EX, the digital bit
stream will contain a “flag” which tells the Cinema Reference Mach
II that it has been specifically mixed and mastered to take into con-
sideration a playback system that has one or two surround back
speakers. While a standard 5.1 mix can be engaged to play through
a 7.1 or 6.1 speaker system, Dolby Digital Surround EX material is
specifically mastered for these systems. In the event that you have
only a 5.1 speaker array in your system and you are playing a Sur-
round EX DVD, the Cinema Reference Mach II will redirect this in-
formation to the surround speakers in place. Please note, that even
a Dolby Digital Surround EX signal is still only considered to be a 5.1
channel mix (or 3.2.1.0) because the surround back channel is not
discrete.
DTS, DTS ES Matrix, and DTS ES Discrete
DTS, much like Dolby Digital is most frequently mixed in a 5.1 for-
mat or 3.2.1.0. Also, similar to Dolby Digital Surround EX, material
encoded with a DTS ES Matrix will contain a flag in the digital bit
stream that indicates that this material was specifically mixed with a
mono surround back image contained in the left and right surround
channels. While this mix is intended to play through a 7.1 or 6.1
speaker array, it is still only a 5.1 (or 3.2.1.0) mix in that there are
only six discrete encoded channels.
DTS ES Discrete is a more involved encoding format in that it is a
true 7.1 or eight channel mix. Here there are two additional chan-
nels in the bit stream and the source material is a true 3.2.1.2 mix,
where the last 2 refers to the additional two channels for surround
back left and right. In the event you are playing a source encoded
with DTS ES Discrete through a system that is setup with either a
5.1 or 6.1 speaker array, the Cinema Reference Mach II will redirect
the information to either the single surround back speaker or in if it is
not present, the two surround back speakers.