JBL S4800, Руководство пользователя

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CHAPTER 5 – PLACEMENT AND SETUP CONSIDERATIONS
The S4800 loudspeaker system is
designed to be less affected by
room acoustics than conventional
imaging systems. However, it is
very sensitive to overall symmetry,
and proximity to walls, ceilings and
corners.
Ideally, any listening room should
contain a combination of live sur-
faces (e.g., walls and windows)
and absorbent surfaces (e.g.,
drapes, carpets, upholstery). If
the distance from floor to ceiling
is short, it is preferable that one
surface has an absorbent cover-
ing. With the S4800, it is most
important to be able to accommo-
date the optimum listening area
that is defined by the 100° hori-
zontal/60° vertical coverage
pattern of the horn.
The listener should be centered in
front of the speakers, and furniture
should be of an appropriate height
so that when the listener is sitting,
his or her ears are level with the
horn (approximately 32 inches/
80cm), as illustrated in Figure 2.
CAUTION: The S4800 is a massive
system comprising materials chosen
for their density, with its weight
concentrated in a relatively narrow
area. Verify the integrity of the floor
surface before placing and setting
up the speakers. See
Floor
Requirements.
If possible, the distance between
the speakers should be the same
as the distance between each
speaker and the listening area.
Angle the speaker in toward the
listener so that when seated, the
listener can look straight into the
center of the speaker (Figure 7). As
the distance increases between
the speakers, increase the inward
angle of the speaker.
The imaging qualities enable the
speakers to be placed relatively far
apart from each other. In addition,
the low-frequency alignment fea-
ture enables placing the speakers
near, or even in, a corner without
producing an overabundance of
bass. This corner placement ability
allows optimum performance even
in small rooms.
The S4800 system can operate
fairly close to the wall. Leave
enough clearance between the
back of each speaker and the wall
to allow for making the connec-
tions on the back of the speaker
(approximately 2 inches – 3 inches
is sufficient), and to avoid interfer-
ence with the performance of the
tuned port. Remember that these
speakers weigh close to 143 lb
(65kg) each and cannot be easily
moved.
FLOOR REQUIREMENTS
The floor in the location selected
for setting up the S4800 speakers
must be capable of supporting a
load of 143 lb (65kg) per speaker.
Because of the coupling effect of
the stainless-steel feet, a flat, hard
surface such as wood or linoleum
is preferable. However, the design
of the loudspeaker’s coupling sys-
tem, along with the speaker’s
extreme weight, should result in
excellent performance on any sur-
face, even on carpets.
To prevent indentations on wood
or linoleum floors caused by the
weight of the loudspeaker, always
utilize the enclosed coasters.
Do not set up the S4800 system
directly on a ceramic tile floor; the
concentrated weight might cause
the tiles to crack.
Figure 7. Room placement of S4800 speaker system.
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