Specifications

4 M86 Operation
24
Many recordings are recorded with a somewhat-
narrow sound stage. This studio mixing approach
provides more consistency for monophonic
reproduction. By setting the C/S Image Balance
control toward "sides", perhaps at the 1 o
∗
clock or 2
o
∗
clock position, a full-width perspective can be
restored without sacrificing image clarity.
Some recordings are recorded with a wide image,
or they may seem to have a weak central area.
Older or poorer-quality stereo recordings, especially
if they are on cassette tape, may have a weak
center due to poor phase accuracy between the left
and right channels. Also, certain recording
techniques (such as stereo synthesis) or mike
setups (such as a wide-spaced pair) can cause a
weak center. In any of these situations, the center
can be restored by setting the C/S Image Balance
control more toward “center” to refocus the central
area.
The low-bass level is not affected by the image
process. Signals below 80 Hz are focused toward
the center for consistent balance. Signals above 80
Hz are imaged to the three loudspeakers according
to the way they are recorded. Sound localization is
generally not perceivable by humans below
approximately 80 Hz.
In many installations, it is not desirable or practical
to make adjustments for particular recordings. This
is not a problem. The control can be left in the
straight-up position or adjusted for good balance,
according to the room and sound system, and left
there. Every program source will be imaged exactly
as it was recorded.
When mixing live, the C/S Image Balance control
will change the panning range at the console. To
provide normal left-to-right panning, set the control
at midpoint.
Surround Control Operation
The Surround control adjusts the level of the
surround signal derived from the stereo input signal.
The Discrete Surround input signal is not affected
by this control.
The Surround level control should normally be
adjusted so that the surround outputs provide a
sense of ambience without being distracting. If the
level is too low, you will not hear much surround
signal. If the level is too high, then front left and right
signals will be heard in the surround loudspeakers
which may be distracting to the front stereo image.
As described earlier, another way to adjust the
surround level is to set the C/S Image Balance
control fully clockwise (to "Diff") and then adjust the
surround level so that a surround effect is realized
which is balanced from front to back. A stereo
program source is necessary for this. From the
center of the listening area, the left, right, and
surround loudspeakers should all sound at about
the same level. After the desired surround level is
achieved, set the C/S Image Balance control back
to the Normal (center) position.
If many listeners are located very near the surround
loudspeakers, then it may be desirable to move
closer to the surround loudspeakers when adjusting
their level. The surround level can
∗
t be perfect
everywhere unless a true distributed system with
many loudspeakers is used. It helps if the surround
loudspeakers are placed high above the listeners.
Generally, the surround level can be set once and
no readjustment is necessary. The loudness of the
surround loudspeakers will be dependent on the
surround mix level in the program source.
Adjustment of the C/S Image Balance control for
optimum front sound staging with a particular
recording simultaneously sets the surround output
to its optimum level.
If the C/S Image Balance control is used to widen
the image, the relative level of the surround output
will increase since there will be a larger difference
component. If the C/S Image Balance control is
used to narrow the image, the surround level will
propor-tionally decrease, since there will then be a
smaller difference component. When the C/S Image
Balance is optimally adjusted, the surround
loudspeakers will usually produce sound at the
desired preset level.
Multisonic Mixing
Mixing Live With Multisonic Imaging
Mixing live in stereo with a Multisonic Imaging
System is easier than with a conventional stereo
P.A. system. Sound can be panned to any location
desired, without concern for the audience being
able to fully hear everything. As a sound is panned
further to the left or right, the same signal begins to
emerge in the opposite side, ensuring total
coverage of the extreme front and side audience
areas.
For example, if an instrument is panned fully to the
left, it will also come from the right loudspeaker, at a
level 6 dB lower. It will also be inverted—this is part
of the imaging process—but listeners very close to
the right loudspeaker and far from the left
loudspeaker will not notice the inversion. They will
hear it at a lower level from the right loudspeaker
and that instrument will sound farther away, as it
should, since it is on the left.