Specifications

3 Installation
21
Fig. 15
M86 or M44 Connections with Bridged Center Loudspeaker.
Bridged Center Connection With One Stereo
Power Amplifier
One characteristic of Multisonic Imaging is that the
center-loudspeaker signal is always an exact
electrical sum of the left and right signals. Therefore
it is possible to connect the center loudspeaker in a
bridging configuration so that one stereo power
amplifier can drive all three front loudspeakers.
This economical approach is useful for systems
which will utilize only two-channel stereo (left/right)
signal sources. Three loudspeakers (left, center,
and right) are driven with a single two-channel
amplifier.
A second two-channel amplifier can be used to add
a subwoofer and/or surround loudspeakers.
For this application, the front stereo amplifier needs
a common output ground (i.e.
it is physically bridgeable)
and be capable of driving 1/3
the impedance of one
loudspeaker. For example, if
8-ohm loudspeakers are
being utilized, each channel
of the amplifier should be
able to drive a load of 2.7
ohms. It is recommended that
an amplifier rated at 2 ohms
is selected for this
application.
The loudspeakers should be
identical or at least have the
same sensitivity and
frequency response. Since
the center loudspeaker has
no independent gain control
or signal path, it should match
the left and right
loudspeakers for this
connection. Thus, correct
level balancing will always be
ensured. Once the left and
right channel gains are matched,
the center will inherently be
perfectly balanced.
The discrete center input can
not
be used with the bridged-
center connection. This
connection does not use the
center output. Therefore, the
Discrete Center and 5.1
center inputs cannot be
routed appropriately.
For multi-way systems, the
stereo amplifier can be
replaced with a crossover and stereo-amplifier
group.
The bridged-center connection diagram is shown in
Figure 15
. All connections must have the specified
polarity. Any polarity problem will be revealed during
the setup adjustment procedure and must be
corrected.
The center-loudspeaker positive lead is connected
to the
left positive
(“+”) amplifier output, and the
center-loudspeaker negative lead is connected to
the
right positive
amplifier output, as shown in
Figure 15
. The M44 or M86 Center output is not
used.
The stereo input connections are made in the
normal way. The subwoofer output and surround
outputs may also be used in the normal way, as
shown in
Figure 9
.