Specifications

3 Installation
14
3
System Design and
Installation
Equipment Selection
The complete design of a multichannel sound
system is complex and beyond the scope of this
manual; however some basic guidelines are
included here to illustrate the differences between
multichannel and conventional or stereo systems.
Multisonic Imaging systems are designed much like
conventional stereo systems. The addition of a
center loudspeaker, carefully integrated with the left
and right loudspeakers, is the main difference. With
stereo program sources supplied in the usual way, a
very effective left-center-right or 5.1 format
presentation is created.
The following basic equipment is needed:
1.
An M86 or M44 Multisonic® Imager to provide the
electronic spatial signal separation. If surround
loudspeakers are to be used, then the M86 is
needed. The M44 can be used for left-center-right-
sub (only) systems.
2.
Three loudspeaker systems for the main front
soundstage. They should be identical if possible; at
least the left and right should be identical—the
center should match them if possible but the system
will be tolerant of a mismatched center loudspeaker,
as described below.
3.
For an M86 Multisonic® surround system,
surround loudspeakers are needed. These are often
distributed around the sides and rear of the listening
area. Any number of surround loudspeakers can be
driven by the M86. For systems which need
directional rear loudspeakers (as sometimes utilized
in discrete 5.1 mixes), usually only two are used
(left rear and right rear).
4.
Subwoofer loudspeaker system(s) if utilized.
5.
The appropriate number of power amplifiers to
drive all of the loudspeakers. Note: for small
systems with identical left, center, and right
loudspeakers, a single stereo power amplifier may
be utilized to drive all three. See page 21.
6.
Any other necessary stereo or multichannel
signal processing equipment. See the section
discussing Other Signal Processing.
There are many factors affecting the design of a
multichannel system. Primary areas of concern are
room acoustics, equipment selection, and
loudspeaker placement.
Loudspeakers
Of course sound quality is usually the primary
concern for loudspeaker selection. In general one
ought to use the best-sounding loudspeakers
available within the sound-system budget. However
another critical parameter, especially for larger
venues, is the directivity, or coverage angle of the
loudspeakers.
The three main front loudspeaker systems should
match each other as closely as possible. The
simplest approach which works well in medium or
small venues, is to use identical loudspeakers for
left, center, and right. However, a basic concept of
Multisonic Imaging is that each of the three main
loudspeaker systems should cover the entire
listening area if possible. While the use of identical
left and right loudspeaker systems is usually easily
accommodated, in larger systems, or those serving
a wide audience, the center loudspeaker may need
to be different since it must have a wider coverage
angle.
In that case, the center loudspeaker should be
equalized to match the left and right loudspeakers
as closely as possible, in terms of frequency/phase
response. This will allow good phantom imaging
between left and center, and between center and
right.
Another approach is to use a two-sided loudspeaker
cluster for the center, where each side of the cluster
is the same as the left and right loudspeakers but
only has to cover half of the audience. This ensures
that the sound of the center will match the sides.
Power Amplifiers
In general, a power amplifier channel is needed for
each loudspeaker system. Of course additional
amplifier channels are needed for actively-crossed-
over loudspeaker systems.
In most cases three amplification signal paths are
needed for the front sound stage, and at least two
more are needed for surround operation. A
subwoofer system usually can be monophonic,
using only as many amplifiers and loudspeakers as
are needed for adequate output level and coverage.
For moderate levels or small rooms, a six-channel
amplifier such as the Miles Technology MPR-450 is
a perfect, cost-effective solution. It can drive left,
center, right, two surrounds, and a subwoofer
channel.
For larger venues or live sound reinforcement,
separate amplifiers of the appropriate size should
be used. Primary concerns for the amplifiers are
good sound quality and enough power to produce
the desired sound level with adequate headroom.