For more than 60 years, JBL has been providing audio equipment for concert
halls, recording studios and movie theaters around the world, and has become
the hands-down choice of leading recording artists and sound engineers. With
the JBL LS Series, innovative technologies such as pure-titanium compression
drivers, Elliptical Oblate Spheroidal
™
(EOS) waveguides and PolyPlas
™
transducer
reinforcement are available to you. Enjoy!
UNPACKING THE SPEAKERS
If you suspect damage from transit, report it immediately to your dealer.
Keep the shipping carton and packing materials for future use.
PLACEMENT
Since the installation of a subwoofer can be somewhat more complicated
than installation of full-range speakers, it is essential that you read this section
very carefully prior to connecting the subwoofer to your system. Should you
have questions relating to your installation, it is advisable to call your dealer or
distributor for advice.
The performance of the subwoofer is directly related to its placement in the
listening room and how you align the subwoofer with its satellite speakers.
Setting the volume of the subwoofer in relation to the left and right speakers is
also of critical importance because it is essential that the subwoofer integrate
smoothly with the entire system. Setting the subwoofer’s volume level too high
will result in overpowering, boomy bass. Setting the volume level too low will
negate the benefits of the subwoofer.
Here are several additional facts on installation that may prove useful. It is
generally believed by most audio authorities that low frequencies (below 125Hz)
are nondirectional and, therefore, placement of a subwoofer within any listening
room is not critical. While in theory it is true that the larger wavelengths of
extremely low frequencies are basically nondirectional, the fact is that, when
installing a subwoofer within the limited confines of a room, reflections, standing
waves and absorptions generated within the room will strongly influence the
performance of any subwoofer system. As a result, specific location of the
subwoofer becomes important, and we strongly recommend that you experiment
with placement before choosing a final location.
Placement will depend upon your room and the amount and quality of bass
required (for example, whether or not your room permits placement of the
subwoofer near either satellite).
Figure 1. This example shows the subwoofer positioned behind
the right-channel satellite speaker to re-create the actual location
of bass instruments in an orchestra and/or add impact to movie
soundtracks.
JBL
®
LS120P POWERED SUBWOOFER
3
INSTALLING SPIKED FEET
Four metal spikes are supplied for use when the speaker is to be placed on a
carpeted surface; using them decouples the speaker from the floor to prevent
unwanted damping. To insert the spikes, gently lay the speaker on its side (not
its front or back) on a soft, nonabrasive surface, and unscrew the rubber-tipped
feet (store in a safe place). Each spike then screws into the threaded insert in
each corner. Make sure all four spikes are screwed in completely for stability.
To protect the surface of uncarpeted floors, set each spike into an included
metal coaster.
NEVER drag the speaker to move it, as this will damage the spikes, the feet, the
wood cabinet itself, and/or the floor. Always lift the speaker and carry it to its new
location.
JBLP2555LS120P-120Vom 4/16/08 1:12 PM Page 3
