JBL Synthesis SAM3HA - Manual (Page 5)

N
OTE
: It is extremely important to place the tweeter/mid-bass arrays for each of the center, left and right speakers
at the same height. The horn array containing the tweeter in the center channel speaker should be no more than two
feet (0.6 meter) higher or lower than those in the left and right speakers. This preserves the “localization integrity” of
“sound pans,”in which the sound appears to move from left to center to right. If the program material also appears to
travel up and down, it can destroy the illusion of panning effects and so should be avoided.
A
MBIENT
S
URROUND
S
PEAKERS
: Although it has been common for many years to use a number of surround
speakers in commercial movie houses, until recently, the traditional home theater configuration called for 5.1
channels, i.e., front left, center, front right, surround left and surround right, plus a low-frequency-effects channel.
The newer surround formats that are appearing in consumer audio equipment are calling for more complicated 6.1-
and 7.1-channel systems. The advantages of using additional speakers are many. Additional channels enable a more
versatile use of directionality for a more accurate surround presentation. Also, a higher overall sound-pressure level
can be achieved with less energy expenditure from any individual speaker. Placement of the surround speakers
remains critical.
5.1-C HANNEL S YSTEMS
The ambient surround speakers work optimally if they are placed as far back
from the screen as the viewing chairs are. If there are two rows of chairs,
these speakers should be placed between them.
The ambient surround speakers should be placed higher than the seating
area, at least two feet (0.6 meter) above (seated) ear level (see Figure 4).
The preferred method to mount the ambient surrounds is to put them directly in
the side walls. This lets each speaker radiate to the front and back of the room
and to reflect off the side walls.
There are a few instances in which the ambient surrounds would perform
better if mounted in the ceiling rather than the walls. If one or both of the walls
are “acoustically dead,”due to the presence of windows, fabric, furniture or
other absorption, it may be necessary to turn the ambient speakers sideways
and, instead of mounting them in a vertical orientation, mount them in the
ceiling in a horizontal orientation.
6.1-C HANNEL S YSTEMS
A 6.1-channel system can be thought of as a 5.1-channel system with the
addition of a rear center speaker placed midway between the two surround
speakers, and further to the rear than the surrounds. It should be placed at the
same height as the side surround speakers (see Figure 5).
5
R C L
FLOOR PLAN
Figure 5. 6.1-Channel system
M
in
.2
'-0
"
Figure 4.
S
PEAKER
P
LACEMENT
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