Miles Technology Multisonic M44, Руководство по эксплуатации

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3 Installation
17
Room Acoustics
The optimum achievable quality of stereo imaging is
very dependent on the room acoustics. Generally,
the deader the room, the better the imaging. Live
rooms provide their own ambience which can be
detrimental to the sound system. Any hard flat
surface, of large area, will create sound reflections
which can be especially harmful to imaging and
overall sound quality. Such surfaces may need
acoustic absorption treatment, especially if they are
near or opposite the loudspeakers.
Of course very dead (anechoic) rooms are usually
not practical, nor even desirable, since they require
much more amplifier power to achieve a given
sound level. Generally the optimum situation is a
room which is fairly dead behind and to the sides of
the loudspeakers, while providing diffused sound
reflections from the remaining areas.
Loudspeaker Placement
Loudspeaker placement is very important for good
imaging performance. While conventional setups
are often optimized for maximum audience
coverage, good stereo imaging goes beyond
that—it is also necessary to optimize the dispersion
and the time alignment between the loudspeakers.
In a traditional two-loudspeaker system, the
soundstage is automatically created on a line from
the left loudspeaker to the right loudspeaker with
little expectation of good imaging for off-center
listeners. However, the Multisonic Imaging concept
is intended to maintain the front-line soundstage, to
focus it better, and to allow listeners to be far from
center and still hear the stereo image correctly. This
can be achieved if the loudspeakers are set up
correctly; a bit more care is needed for the best
possible imaging performance.
To the extent possible, each of the three front
loudspeakers should cover the entire listening area,
so that every listener can hear each of them. Large
venues may require loudspeaker clusters with
appropriate dispersion performance designed to
cover the entire audience from each of the three
locations.
In medium or small rooms individual loudspeakers
can often be used with excellent results. It can be
advantageous for the left and right loudspeakers to
be aimed somewhat inward so that the opposite
side coverage is balanced in level with the same-
side coverage. Even if the loudspeakers cannot
cover the entire audience, success can still be
achieved due to the forgiving nature of Multisonic
Imaging. Those who are outside the area covered
by one of the loudspeakers will still hear the entire
mix, with some degree of sound staging across the
loudspeakers which they can hear.
General Placement Concept
The basic concept for loudspeaker placement is
shown in Figure 10. While this shows a typical
small-room setup with surround, it can also be
proportionally applied to larger rooms. In this case,
two types of surround loudspeakers are
shown—dipole loudspeakers at the sides, and
standard (forward-radiating) loudspeakers at the
rear corners. In typical small rooms, either type can
be used, or both pairs can be used together with
excellent results.
Fig. 10 Loudspeaker placement for Multisonic
Imaging with surround.
In a typical small room the front loudspeakers
should normally be about three to five feet (1 to 1.6
meters) high; the surround loudspeakers should be
higher, near the ceiling. In larger rooms, all the
loudspeakers should be high enough to provide
even coverage to as much of the listening area as
possible.
Figure 11 shows a setup for a larger venue, using
clusters for wide coverage. The dashed lines show
the left-center and right-center optimum phantom
positions. Listeners along these lines will
hearperfect phantom imaging of sounds panned to
locations between the loudspeakers. The point
where they intersect should be toward the back
from the center of the listening area. This provides