Bowers & Wilkins 800 Serie Mode D'emploi page 8

Electrical connections
Disconnect all sound system equipment from the
power supply until the signal connections have been
made and checked. This avoids the risk of damage
whilst connections are made or broken.
The function of the subwoofer is to receive signals
from the amplification chain and, where necessary for
2-channel audio, split the signal into low bass and
higher frequencies and feed the latter back out to the
satellite speakers. Left and right channel inputs may
be combined into a single mono low bass feed to the
subwoofer drive unit if required.
The subwoofer will input and output line-level signals
via the RCA Phono sockets located on the back panel.
Use the following table to select the correct wiring
method for your installation:
Application: Home Theatre
The subwoofer may be used with any decoder that
has a line-level subwoofer output (normally from an
RCA Phono socket). Most decoders with integral
power amplifiers still output the subwoofer or Low-
Frequency Effects (LFE) signal at line level.
• Decoder with one or more subwoofers – fig. 3
Application: 2-channel audio
Separate pre- & power amplifiers:
a One or more subwoofers with output combined
into a single mono signal – fig. 4
b Two subwoofers with separate left and right signal
– fig. 5
The subwoofer is not suitable for use with 2-channel
integrated pre/power amplifiers.
Using more than one subwoofer
Using more than one unit in a single installation can
improve performance in the following ways:
• Maintain stereo separation to the lowest
frequencies.
• Cope with larger listening rooms.
• Enable greater maximum sound output – often
useful for effectively reproducing special effects in
Home Theatre applications.
• Smooth out the effects of low-frequency room
resonances.
If you are using two subwoofers for
2-channel audio, separation is improved if each
channel has its own subwoofer, providing each one is
placed close to the relevant satellite speaker. Only use
the mono connection of figure 4 if you cannot place
each subwoofer close to its satellite speaker.
Double-check the connections
Before auditioning the sound quality of your new
installation and fine-tuning it, double-check the
connections. All too often, users complain that they
cannot get a decent sound however they set the
All manuals and user guides at all-guides.com
controls, only to discover something has been wrongly
connected. Make sure that:
•
•
Switching on and off
We recommend that you switch the subwoofer on
before any power amplifiers receiving signals from the
subwoofer. Similarly, when switching off, switch the
subwoofer off last.
The MODE standby/auto/on switch (4) does not isolate
the amplifier completely from the power supply. It
maintains a low-power input to an auxiliary sensing
circuit.
The switch (4) operates as follows:
On:
With the switch in this position, the amplifier remains
permanently on, and the light (1) glows green.
Auto:
On first switching the subwoofer to Auto, the amplifier
becomes fully active and the light (1) glows green.
After a period of about 5 minutes without an input
signal, the amplifier automatically reverts to standby
mode, and the light glows red. When an input signal is
detected, the amplifier automatically becomes fully
active and the light glows green.
Standby:
In this position, the amplifier is in permanent standby,
and the light glows red.
If the subwoofer is to be out of use for an extended
period of time, we recommend you isolate it from the
power supply, either by using the POWER switch (11)
or by removing the plug from the power socket.
Setting the controls
There are 5 controls to consider:
•
•
•
•
•
The optimum settings depend on the other equipment
used with the subwoofer. If using more than one
subwoofer, ensure the controls on each one are set
the same.
The phasing is correct – there should be no
positive to negative connections to the satellite
speakers. If something is out of phase you may get
a fuzzy sound with an imprecise and floating
image, a lack of bass or a combination of the two.
There are no left to right mix-ups – this can result,
for example, in the orchestra being the wrong way
round or, more disastrously, sounds on your Home
Theatre going in the opposite direction to the
action on the screen.
The VOLUME control (2)
The LOW-PASS FREQUENCY control (3)
The PHASE switch (7)
The LOW-PASS FILTER switch (6)
The EQ (equalisation) switch (5)
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