The two 1/4" phone jacks on the 115sA/118sA are The placement of any speaker can dramatically
wired in full parallel so that any one of the connectors affect its sound. Thus, there are three primary
may be used as an input and the other connector as considerations to review when placing subwoofers.
an output to another enclosure. This allows multiple
cabinets to be "daisy chained", eliminating the need The first is time alignment. The full-range speaker
for several long runs of speaker cable.
s ys tem s hould be as clos e as pos s ible to the
s ub woofe r s o the s ound from the s ub woofe r
Note: A single 115sA/118sA subwoofer represents reaches the audience at the same time as the sound
an 8Ω load to the amplifier. Daisy chaining two of from the full-ra nge s p e a ke r s ys te ms . If the
them in parallel will represent a 4Ω load to the subwoofer is placed too far from the full-range
amplifier. Only amplifiers rated for 4Ω output should speaker systems, a slight smearing of the lower
be used in this configuration.
bass frequencies may occur. While ideal placement
for this consideration would involve stacking the full-
The following polarity convention should be used range speaker on top of the subwoofer, this effect is
when making connections to the 115sA/118sA:
quite subtle and an obvious effect may not be heard
until the separation between the two cabinets is large
enough to cause an audible time delay.
The s e c ond consideration is to try to obtain as
much bass as possible from the subwoofer. A
speaker in the middle of the floor or up in the air with
its back against a wall is referred to as operating in
USING THE 115sA/118sA IN A SYSTEM
"half space". Placing a speaker near a large, flat wall
and on the floor (quarter space) will boost the bass
The 115sA/118sA is designed to augment the low performance by about 3 dB as compared to half
frequency performance of the main P.A. speakers. space. The more surfaces the subwoofer is placed
The single reflex bandpass design of these systems a ga ins t, the fe we r the numb e r of s ub woofe r
a utoma tic a lly rolls off the high fre q ue nc ie s enclosures are needed to achieve a desired SPL.
eliminating the need for an active or electronic
crossover network. Thus, the subwoofers can be The third consideration is convenience and the
wired directly in parallel with almost any full-range visual aspect of the speaker array. For temporary
ins tallations , the s ubwoofer can be us ed as a
support for a full-range speaker system mounted
Nonetheless, a line-level electronic crossover, such directly on top of the subwoofer. Use only the 27”
as a Fender PCN-2 or PCN-4 , can be used in Fender Mounting Pole (P/N 711327) which has
ord e r to s p lit fre q ue nc ie s a nd s e nd mid /high been specifically designed for use with both the
frequencies to a full-range speaker system and low 115s A/ 118s A s u b wo o fe r e n c lo s u re s . In
frequencies to a subwoofer. By reproducing high permanent installations, the 115sA/118sA can be
levels of low bass frequencies, the 115sA/118sA placed under a stage, table, or podium.
relieves the smaller main speakers from having to
supply this energy. If a crossover is used in your For each particular situation, a compromise among
set-up, make sure that the crossover point is these three factors should yield the best solution
b e twe e n 100/ 120 Hz to e n s u re m a xim u m possible.
efficiency from your 115sA/118sA.
Two different configurations are shown on pages 5
and 6, demons trating how eas y it is to add a
subwoofer to your system. Figure 3, on page 7,
shows a more extensive configuration for those set-
ups requiring additional power.