Cambridge Audio 551R User Manual

Set the Decode mode as 5.1 or 7.1 by highlighting the Decode Mode item and

using the Left and Right arrows to scroll through the options:

Now move down and by highlighting each speaker in turn and using the Left

and Right arrows select from ‘Large’, ‘Small’ or ‘None’ for each speaker.

'Large' or 'Small' are used to describe each speaker in terms of bass

response, they do not necessarily reflect the actual physical size of the

speaker.
Large = Speakers with an extended low frequency response of approximately

20-40Hz to 16-20kHz (floorstanders or high quality larger stand-mounted

speakers).
Small = Speakers with a less extended low frequency response of

approximately 80-100Hz to 16-20kHz (small stand-mounted, bookshelf or

satellite speakers).
Setting each speaker allows the 551R to perform what is called Bass

Management and to direct low frequency bass from music and the Low

Frequency Effects channel of surround sound material to those speakers

best able to reproduce it. If you do not wish to use any of the speakers set its

setting to ‘None’.
The Subwoofer output can also be set to Yes or No. If no sub is being used

make sure this setting is set to No to allow the 551R to re-direct the bass

information in this channel to other speakers.
Note: The 551R will force some speakers to certain settings in the following

circumstances!
The Front Left and Right speakers may be ‘Large’ or ‘Small’ but never ‘None’

as they are always required for any type of music/movie reproduction.
Bass must always be reproduced by either the Front Left and Right or

Subwoofer channel (or both). Setting the Front Left and Right to ‘Small’ will

result in the Subwoofer automatically being set to ‘Yes’. Setting the

Subwoofer to ‘No’ will automatically result in the Front Left and Right being

set to ‘Large’.
If the Front Left and Right cannot reproduce low frequency bass a Subwoofer

must be used. I.e. If the Front Left and Right are set as ‘Small’ the Sub must

be Set to ‘Yes’.
Also, setting the Front Left and Right as ‘Small’ will always set the other

speakers as ‘Small’ (and the Sub to ‘Yes’). This is because LFE/ bass

information should not be redirected to the surround channels.
To store the setting simply come back out of the OSD (pressing the OSD

button always moves back one menu item, and then exits and stores from

the main menu screen).

551R

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The following two sections can be performed by Cambridge Audio CAMCAS

procedure so you can if you wish jump straight to that section. However, it is

recommended that you do read these sections to understand the reasons for

these settings and their implications.

Speaker delay

Because the speakers in a surround sound system are usually different

distances from the listener the 551R incorporates the ability to apply a

variable digital delay to each of the channels so that the sound from each

arrives at the same time at the listening position for best surround-sound

effect.
To set the delay times automatically, refer to the Auto setup section of this

manual.
To set the delay times manually, simply measure the distances from the

listening position to each speaker as shown in the following diagram:

Note: No delay setting for the subwoofer is necessary.
Set the distances in the OSD Speaker Distance menu to the nearest value in

metres (1 foot = 0.3 metres). The speed of sound is approx 340 metres per

second, the 551R thus introduces approx 3mS of delay per metre of distance

set.
Go to the ‘Speaker Distance’ and highlight each speaker in turn. Set the

distance to the nearest value to that which you measured by using the Left

and Right arrows (the values do not need to be exact):
Press the OSD button to exit the menu.

Note: In addition to the delays as set above Dolby Pro Logic II/IIx playback

also requires an extra 15 milliseconds delay to the surround channels only.

This extra delay is part of the Dolby ProLogic II specification and ensures that

sound from the surrounds arrives just after sound from the front reducing the

audibility of sound leakage from the front to the surround speakers. Because

the relationship between the Dolby Digital and Dolby ProLogic IIx two delays

is fixed (15mS extra to the surround channels), it is only necessary to set the

delay by measuring the distances as we have described. The 551R will

automatically provide the appropriate extra delay whenever you switch to a

Pro Logic Mode.

1 = Front Left speaker
2 = Front Right speaker
3 = Centre speaker
4 = Surround Left speaker
5 = Surround Right speaker
6 = Surround Back Left

(when used)

7 = Surround Back Right

(when used)

8 = Subwoofer (can be placed

almost anywhere)

2. Speaker setup

Speaker Distance Menu

Unit

Front L

Front R

Centre

Surr. L

Surr. R

Surr. LB

Surr. RB

Return : [OSD]

Meters

2.9
2.9
2.9
2.0
2.0
2.0
2.0

Speaker Config Menu

Decode Mode

Front L/R

Centre

Surr. L/R

Surr. LB/RB

Subwoofer

Return : [OSD]

7.1

Large
Small
Small
Small

Yes

ENGLISH