JBL SB210 - Manual (Page 8)

Adjusting Volume of 70V/100V System
Adjust the tap setting to change the amount of power that
gets to the entire sub/sat system.
Multiple Systems
Multiple sub-sat systems can be utilized on a single
70V/100V distributed speaker line. Each can cover a
different area with full-range sound. Systems can be mixed
on a 70V/100V line as long as all the systems utilized the
MTC-210T-SAT module. See Figure 2.
Subwoofer Distance Consideration
Even though it’s not easy for the human ear to tell where the
sound from a subwoofer is coming from (non-localizable),
that doesn’t mean that a single subwoofer can always cover
an entire space.
The sound level from a subwoofer is louder nearby to the
subwoofer and quieter farther away from it. As rooms
get larger the level variation gets more uneven because the
distance from the subwoofer gets longer. It may be necessary
to add a second subwoofer on the other side of the room.
Locating multiple subwoofers near the center of opposite
walls within the room often works well, resulting in more
even coverage of the entire room.
When greater subwoofer output is desired, an alternative is
to locate the subwoofers near opposite corners of the room,
although the subwoofers can get excessively loud in those corners
compared to the rest of the room.
For rooms where very even subwoofer coverage is desired, a
distributed subwoofer system might be a better solution than using
one of the passive subwoofer/satellite systems from this guide. If
so, see the subwoofer chapter of the JBL guide entitled Designing
Better Sounding In-Ceiling Business Music Systems.
Affect of Room Size on Sound Level
The Max SPL figures listed for each system are based on a listening
distance of approximately 20 feet.
For larger rooms where some listeners will be father than 20 feet
from the speakers, the true sound level capability of the sub-sat
system will be lower. For example, the Max SPL level at 40 feet
-- twice the listening distance -- will be 6 dB lower than the listed
figure.
In addition, as the room gets larger, there will be more level variation
of the sound from both the satellite speakers and the subwoofer
from place to place within the room. This can lead to unacceptably
high variations in sound level, where the sound might be too loud
in some areas and too soft in others.
In rooms where this is the case, it may be necessary to utilize
more than one subwoofer/satellite system, or to use a more highly
distributed system than a small subwoofer/satellite system is
capable of doing.
Figure 2
Multiple 70V/100V sub-sat systems on a single distributed speaker line.
Low Impedance
Satellite Speakers
Set system volume with
70V/100V tap switch
Low Impedance
Satellite Speakers
ROOM 1 ROOM 2 ROOM 3
70V/100V Distributed Speaker Line
70V/100V Input
to Subwoofer 70V/100V Input
to Subwoofer
Set system volume with
70V/100V tap switch
70V/100V Input
to Subwoofer
Set system volume with
70V/100V tap switch
Low Impedance
Satellite Speakers
70V/100V Amplifier
From
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