JBL Synthesis S4S - Manual (Page 3)

3
S
PEAKER
P
LACEMENT
Low-frequency sounds are normally omnidirectional, meaning the listener can’t tell where they are generated from.
However, frequencies between 75Hz and 150Hz can be localized, especially at higher volume levels. Positioning your
subwoofer as recommended will provide the most natural soundstage and imaging from your loudspeaker system.
It is generally recommended that you install your S4S in-wall subwoofer along the same wall as the front loud-
speakers. The S4S subwoofer is not video-shielded and should not be placed near a video display. Installing the
S4S near a corner will tend to maximize low-frequency output. Be cautious when installing in a corner, to avoid a
“boomy” sound. Also take into consideration any unusual features of the room, such as an alcove, which may tend
to create a localized node that may affect bass response in that area of the room.
It is also recommended that the speaker be installed so that the bottom of the speaker is approximately 12" from the
floor. Using the S4SBB back box enclosure will ensure that the loudspeaker is installed at the ideal height. This is to
help with the low-frequency loading (bass reinforcement). This also helps hide the speaker in a less visible place. In
special circumstances it is acceptable to install the speaker at any height on a wall.
Remember that these are just guidelines. Since every listening room is different, JBL strongly recommends experi-
menting with the positioning of your subwoofer prior to cutting the wall to obtain the most pleasing results in your
room. One technique that can help you find the ideal subwoofer location is to temporarily borrow a stand-alone sub-
woofer and place it near the main listening location. Then move around the room and determine where you hear the
most pleasing bass performance. This would then be the ideal location for the subwoofer.
A single S4S subwoofer system meets THX ® Select requirements for a 3000-cubic-foot room. However, to meet
THX Ultra2 ™ requirements for a 3000-cubic-foot room, two or more S4S subwoofer systems are required, using
a total of four woofers. For every additional 3000 cubic feet of room volume, it is recommended that one
additional S4S system be added.
When using two S4S in-wall subwoofer systems, you may need to be concerned about phase, as the sound waves
may cancel each other out. If bass response seems low, try inverting the polarity on one subwoofer – i.e., connect
the (+) terminal on the amplifier to the (–) terminal on the speaker, and the (–) terminal on the amplifier to the (+)
terminal on the speaker.
S4S OM 10/18/05 12:02 PM Page 4