Specifications

3 Installation
16
loudspeaker (after the Imager). Each loudspeaker
system can be equalized independently. This is
applicable for clusters, multi-way systems, and
unmatched center loudspeakers.
However, if only one stereo source is to be used,
then a two-channel stereo loudspeaker equalizer
may be placed just ahead of the Imager; this way it
will correct
all
of the loudspeakers (left, center, right,
left surround, right surround, and sub).
Main Crossovers
While an active subwoofer crossover is built into the
Imager, larger multiway systems will need external
active crossover filters for the higher-frequency
crossover points. For multi-way systems, the left,
center, and right outputs should go to three
crossover systems to drive three amplifier groups.
To the extent possible, the three
crossover-amplifier-loudspeaker groups should be
adjusted to produce matching sonic results.
Protective Limiters
Protective limiting should normally be the last thing
before the power amplifiers. This allows adjustment
of the other signal processing without upsetting the
calibration of the protection thresholds. In addition,
special loudspeaker processing or sense-line
loudspeaker protection should normally be just
ahead of the power amplifiers.
Mono Output
If a mono output signal is needed in addition to the
Multisonic outputs, the Center Output can be used
for this purpose. It will contain a mono (left-plus-
right) mix of the stereo input signals combined with
the discrete center input signal. The center output
connection can drive multiple line-level devices up
to its loading limit.
The center output signal can be used to drive a
mono delayed speaker array, for example (see
below). If a 5.1 source is used in this application,
the “5.1-to-Multisonic” switch should be pressed so
that the left and right channels of the 5.1 source will
also be mixed into the mono (center) signal.
Multisonic with Delayed Loudspeakers
A popular technique for improving the coverage of a
sound reinforcement system is to use additional
loudspeakers with delay. These are placed to cover
areas at the fringes or rear of the listening area
where additional loudness is needed.
These loudspeakers operate with a delayed signal
so that they can provide the additional loudness
without disrupting the sound staging. The amount of
delay is set so that the sound from the main system
arrives at the listener just before the delayed sound,
usually by about 15 to 30 ms. This helps to retain
the sound localization of the main system.
This approach works well with a Multisonic system.
There are basically three ways to create the delayed
signals—the optimum method depends on the
physical configuration of the room. The main front
system is set up in the usual way, with left, center,
and right loudspeakers. When properly set up and
adjusted, Multisonic Imaging localization can
generally be retained for those in the delayed
coverage areas.
(1) Distributed Mono Delay
This can work well for rooms of virtually any size
and shape, and is particularly suitable for very wide
rooms, and over or under balconies. Any number of
additional loudspeakers are placed such that each
covers a part of the rear or extreme-side audience
area. The
center output
signal from the M86, which
also drives the main center loudspeaker, is delayed
and used to drive the additional mono
loudspeakers. If necessary multiple delay times are
used, and the levels may need to be adjusted
separately, depending on the physical setup.
(2) Conventional Stereo Delay
This works for rooms which are longer than they are
wide, and a delayed center loudspeaker is not
practical. Additional left and right loudspeakers are
set up to cover the rear audience area.
In this case, a standard left/right stereo output signal
is needed. This can be reconstructed from the M86
outputs in balanced (symmetrical) form by using
Left + and Center - for the left output, and Right +
and Center - for the right output. This way the left
and right will also carry the center-panned
information. The reconstructed left/right signal
drives the stereo delay system.
Since the delay system is stereo, the two
loudspeaker systems should be angled inward so
that each covers as much of the rear audience area
as possible. This approach can provide a greater
sense of space and improved imaging compared to
a mono delay system.
(3) Multisonic Delay
This works well for rooms which are longer than
they are wide. Additional left, center, and right
loudspeakers are set up to cover the rear audience
area. The left, center, and right outputs from the
M86, which are used for the main system, are also
delayed and used to drive additional loudspeakers
which are located above the audience to cover the
rear audience area.