Cambridge Audio 551R User Manual

551R

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Known also as DD (3/3) or DD 6.1, an enhanced form of Dolby Digital. On top

of the discretely encoded 5.1 channels DD EX provides an extra 6th channel

(Surround Back, giving 6.1) matrix encoded into the rear surrounds for

greater image depth and more solid sound localisation behind the listener.

DD EX requires a DD EX encoded disc. DD EX is backwards compatible with

DD 5.1 decoding. If DD EX is decoded as normal DD the Surround Back signal

will be present in both Left and Right Rear Surrounds (forming a phantom

rear centre). It can also be decoded as 7.1 by sending the Surround Back

decode to both the Surround Back Left and Right speakers (forming two

mono Back Surrounds).

Known also as DTS (3/3) Matrix, an enhanced form of DTS. On top of the

discretely encoded 5.1 channels DTS ES also provides an extra 6th channel

(Surround Back giving 6.1), matrix encoded into the rear surrounds for

greater image depth and more solid sound localisation behind the listener.

DTS ES requires a DTS ES encoded disc. DTS ES material is backwards

compatible with DTS 5.1 decoding. If DTS ES is decoded as normal DTS the

Surround Back signal will be present in both Left and Right Rear Surrounds

(forming a phantom rear centre). It can also be decoded as 7.1 by sending

the Surround Back decode to the both the Surround Back Left and Right

speakers (forming two mono Back Surrounds).

Another enhanced form of DTS, also known as DTS (3/3) Discrete or DTS ES

Discrete 6.1. DTS ES Discrete also provides an extra channel (Surround Back)

for greater image depth and more solid sound localisation behind the

listener, however in this case extra data is included in the bitstream so that

all channels are discretely encoded. The Surround Back has greater

separation from the other channels than is possible with matrix encoded

technologies. DTS-ES Discrete requires a DTS-ES Discrete encoded disc.
DTS ES Discrete is backwards compatible with both DTS 5.1 and DTS ES

Matrix 6.1 decoding. If DTS ES Discrete is decoded as normal DTS the

Surround Back signal will be present in both Left and Right Rear Surrounds

(forming a phantom rear centre). If DTS ES Discrete is decoded with DTS ES

Matrix the Surround Back signal will be decoded separately (i.e. as 6.1) but

by a matrix process, which will give the same channel separation as if the

source disc were actually DTS ES Matrix (but not as good as DTS EX Discrete).
It can also be decoded as 7.1 by sending the Surround Back decode to both

the Surround Back Left and Right speakers (forming two mono Back

Surrounds).

The replacement for the original ProLogic, Pro Logic II is a technology where

5 channels (Front Left, Front Right, Centre, Surround Left, Surround Right)

are encoded into a Stereo mix by an analogue matrix process. Dolby Pro Logic

II material can be played back by normal Stereo equipment (as Stereo) or

decoded into 5 channel surround-sound.
Dolby Pro Logic II is compatible with the earlier 4 channel (Left, Centre, Right

and mono Surround) Dolby Pro Logic system (which was the decoding

counterpart to Dolby Surround encoding) as used widely on Video tapes, TV

broadcasts and earlier films.
Note: Pro Logic does not include a Low Frequency Effects channel for the

Subwoofer, but the 551R can create a Subwoofer output (for 5.1) via Bass

management. Refer to the ‘Tone/Sub/LFE configuration’ section in the

‘Operating instructions’ part of this manual.

A newer version of Dolby Pro Logic II which is able to recreate 7 discrete

surround sound channels from suitable encoded stereo source material. Pro

Logic IIx also has modes for post processing either Stereo material or 5.1

material into 7 channels whether or not it has been Pro Logic IIx encoded.

When 5.1 decoding is required, Dolby Prologic II decoding will always be used

by the 551R in place of Pro Logic IIx as IIx only works for 7 channel output.
Note: Pro Logic IIx does not include a Low Frequency Effects channel for the

Subwoofer, but the 551R can create a Subwoofer output (for 7.1) via Bass

management. Refer to the ‘Tone/Sub/LFE configuration’ section in the

‘Operating instructions’ part of this manual.

ENGLISH

The 551R supports several music and home-cinema listening modes. The

output the 551R can provide, depends both on the source signal present, the

speaker setup selected and the decode mode selected. Before we describe

how to operate the 551R, below is a brief guide to the Surround Sound

formats that the 551R is compatible with for reference:

Dolby’s lossless audio technology developed primarily for high capacity Blu-

ray discs/players. Dolby True HD delivers theoretically bit-for-bit sound

identical to the studio master by the use of 100% lossless encoding. Previous

formats such as Dolby Digital 5.1 or EX have used lossy encoding where

some data (that is theoretically less audible) is always lost in the encoding

process to reduce the storage capacity needed on the disc. This is a new

format that supports up to eight (usually used as 7.1) full-range channels of

24-bit/96 kHz audio or two channels of 24/192 kHz via Blu-ray discs and is

not backwards compatible with earlier schemes. The format can either be

transmitted as a ‘bitstream’ to the 551R for internal decoding

(recommended) or can be decoded by some Blu-ray players internally and

sent to the 551R as multi-channel PCM. In both cases an HDMI connection

is required to the 551R and a suitable Blu-ray player as Dolby True HD is only

ever transmitted over HDMI.

An encoding scheme based on the original Dolby Digital CODEC, but with

enhancements to improve coding efficiency and improved audio quality.

Dolby Digital Plus supports 7.1 fully discrete channels compared to Dolby

Digitals 5.1 (or 6.1 in its EX variant where the 6th channel is matrix encoded).

These Dolby Digital Plus bitstreams are not backward compatible with legacy

Dolby Digital decoders but require an AV Receiver developed to decode them

(such as the 551R) and an HDMI connection as Dolby Digital Plus is currently

only transmitted over HDMI. It is however a requirement that any Dolby Digital

Plus enabled Blu-ray player must also be able transform the Dolby Digital

Plus into a backwards compatible Dolby Digital 5.1 output for playback on

legacy Dolby Digital systems. The 551R is however fully compatible with

Dolby Digital Plus.

A new lossless audio CODEC from DTS, rather than being incompatible with

earlier versions, DTS-HD Master Audio is transmitted as an extension to a

normal DTS bitstream. A second embedded stream is sent which contains

the "difference" between the original studio master and the lossy

compressed DTS, plus the two extra channels. DTS-HD Master Audio

enabled devices (such as the 551R) are able to use this difference

information to recreate a bit for bit lossless version of the original 7.1 data.

Devices which do not support the Master Audio extension simply decode the

original 5.1 DTS stream and ignore the Master Audio extension providing

backwards compatibility.

DTS-HD High Resolution Audio

Known also as DTS-HR an extension to the original DTS audio format. DTS-HD

High Resolution Audio supports 7.1 fully discrete channels compared to

DTS’s 5.1 (or 6.1 in its DTS ES Matrix or DTS ES Discrete variants). As with

DTS-HD Master Audio a second embedded stream is sent which contains the

"difference" between the original studio master and the lossy compressed

DTS, plus the two extra channels, however in this case the extra stream is

also formed by lossy compression. Effectively this is a 7.1 version of DTS

which can be decoded by devices (such as the 551R) which are able to

decode DTS-HD High Resolution Audio. Devices which do not support the

High Resolution extension simply decode the original 5.1 DTS stream and

ignore the High Resolution extension providing backwards compatibility

Known also as DD (3/2) or DD 5.1, provides (up to) 5.1 output from suitable

encoded Dolby Digital material, with 5 main channels (Front Left, Front Right,

Centre, Surround Left, Surround Right) and a Low Frequency Effects Channel

for the subwoofer, all discretely encoded. Decoding Dolby Digital requires a

Dolby Digital encoded DVD disc and a digital connection from the source

equipment (Such as a DVD player) to the 551R.
Note: Dolby Digital and DTS formats can sometimes carry less channels than

their maximum such as Dolby Digital (2/0) which means a Dolby Digital

encoded signal which is actually only carrying a two channel stereo signal

(other channels inactive).

Known also as DTS (3/2) or DTS 5.1, DTS provides (up to) 5.1 output from

suitable encoded DTS material, with 5 main channels (Front Left, Front Right,

Centre, Surround Left, Surround Right) and a Low Frequency Effects Channel

for the subwoofer, all discretely encoded. Decoding DTS requires a suitably

encoded DTS disc and a digital connection from the source equipment to the

551R.

Surround sound modes