NAIM AV2 Owner's Manual - page 26
24
Decode
Mode
Direct
Mono
Stereo
Dolby PL II
Music
Dolby PL II
Movie
Dolby Digital
Surround EX
DTS Neo:6
Cinema
DTS Neo:6
Music
DTS Neo:6
Auto
Left Front
Centre Right Front Left Surround Right Surround Extra Rear
Sub-Woofer
= =
= =
(Note 1)
= = =
(Note 1)
= = = = = =
(Note 1)
= = = = = =
(Note 1)
= = = = = = =
= = = = = = =
(Note 1)
= = = = = = =
(Note 1)
= = = = = = =
= = = = = =
(Note 2)
=
(Notes 1 & 2)
Table 19.5
Decode Modes and Channel Schemes
19.6 Surround Encoding - Technology
Some feature films have carried the multi-channel sound
tracks necessary for “surround sound” since the 1950s. But
only since the mid 80’s has surround sound been available to
domestic consumers. The technology that first enabled four
channels of audio to be decoded from the stereo soundtrack of
consumer media such as video cassette is Dolby Surround Pro
Logic. Since Dolby Surround Pro Logic, and especially following
the introduction of digital products such as DVD, enhanced
encode and decode technologies have been introduced that
enable a greater number of higher quality channels of audio to
be encoded. With digital encoding techniques such as Dolby
Digital and DTS Surround, appropriately encoded feature films,
music and even computer games can be reproduced in full-
bandwidth surround sound with up to eight audio channels (left,
right, centre, surround left, surround right, surround extra, low-
frequency effects).
The following few paragraphs provide a short description and
explanation of each decode technology and mode available
on the AV2. Further technical information can be found at
www.dolby.com and www.dtsonline.com
19.6.1 Dolby Surround Pro Logic
Dolby Surround Pro Logic is a matrix decoding process that
generates four output signals (left, right, centre, surround) from
a Dolby Surround encoded analogue stereo input signal. It is
built into virtually every home theatre audio system. The nature
of Pro Logic decoding constrains the single surround channel to
relatively narrow bandwidth.
19.6.2 Dolby Surround Pro Logic II
Dolby Surround Pro Logic II is an improved analogue matrix
technology that provides improved surround performance on
Dolby Surround encoded program material. While earlier surround
programme material is fully compatible with Pro Logic II,
appropriately encoded soundtracks can take full advantage of its
enhancements - which include separate full bandwidth left and
right surround channels. Pro Logic II also features two distinct
decoding options for “music” and “movie” programme material.
19.6.3 Dolby Digital
Dolby Digital is a fully digital decoding technology that provides
three full bandwidth front channels, two full bandwidth surround
channels, and one low-frequency effects channel - a channel
scheme known generically as “3/2.1” (or “5.1”). The encoding
technique for Dolby Digital, known as Dolby AC-3, has since
1995 been used on many Video Laser Discs and more recently
on DVD. Dolby AC-3 encoding can also be found on digital
television services. In addition to encoding audio for six channel
replay, Dolby AC-3 incorporates compression techniques that
ease audio data storage and transmission demands and can
enable, for example, a single DVD to carry a complete movie.
19.6.4 Dolby Digital 2/0
A variation of Dolby Digital 3/2.1 is Dolby Digital 2/0. Dolby
Digital 2/0 takes advantage of Dolby AC-3 data compression in
order to reduce the data storage demands of stereo programme
material. The “2/0” denotes the use of just two main audio
channels with no low frequency effects channel. Programme
AV2
The sub-woofer channel will only operate if Bass Mix is selected (see Section 19.7.2).
Note 2:
Operation of these channels will depend on the specific source material format.