Fender 115sA Subwoofer - Manual (Page 4)

The two 1/4" phone jacks on the 115sA/118sA are
wired in full parallel so that any one of the connectors
may be used as an input and the other connector as
an output to another enclosure. This allows multiple
cabinets to be "daisy chained", eliminating the need
for several long runs of speaker cable.
Note: A single 115sA/118sA subwoofer represents
an 8
Ω
load to the amplifier. Daisy chaining two of
them in parallel will represent a 4
Ω
load to the
amplifier. Only amplifiers rated for 4
Ω
output should
be used in this configuration.
The following polarity convention should be used
when making connections to the 115sA/118sA:
Polarity Phone Jack
Positive (+) Tip
Negative (-) Sleeve
The 115sA/118sA is designed to augment the low
frequency performance of the main P.A. speakers.
The single reflex bandpass design of these systems
automatically rolls off the high frequencies
eliminating the need for an active or electronic
crossover network. Thus, the subwoofers can be
wired directly in parallel with almost any full-range
speaker system.
Nonetheless, a line-level electronic crossover, such
as a Fender
® PCN-2 ™ or PCN-4 ™ , can be used in
order to split frequencies and send mid/high
frequencies to a full-range speaker system and low
frequencies to a subwoofer. By reproducing high
levels of low bass frequencies, the 115sA/118sA
relieves the smaller main speakers from having to
supply this energy. If a crossover is used in your
set-up, make sure that the crossover point is
between 100/120 Hz to ensure maximum
efficiency from your 115sA/118sA.
Two different configurations are shown on pages 5
and 6, demonstrating how easy 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.
The placement of any speaker can dramatically
affect its sound. Thus, there are three primary
considerations to review when placing subwoofers.
The first is time alignment. The full-range speaker
system should be as close as possible to the
subwoofer so the sound from the subwoofer
reaches the audience at the same time as the sound
from the full-range speaker systems. If the
subwoofer is placed too far from the full-range
speaker systems, a slight smearing of the lower
bass frequencies may occur. While ideal placement
for this consideration would involve stacking the full-
range speaker on top of the subwoofer, this effect is
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 second 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
"half space". Placing a speaker near a large, flat wall
and on the floor (quarter space) will boost the bass
performance by about 3 dB as compared to half
space. The more surfaces the subwoofer is placed
against, the fewer the number of subwoofer
enclosures are needed to achieve a desired SPL.
The third consideration is convenience and the
visual aspect of the speaker array. For temporary
installations, the subwoofer can be used as a
support for a full-range speaker system mounted
directly on top of the subwoofer. Use only the 27”
Fender Mounting Pole (P/N 711327) which has
been specifically designed for use with both the
115sA/118sA subwoofer enclosures.
In
permanent installations, the 115sA/118sA can be
placed under a stage, table, or podium.
For each particular situation, a compromise among
these three factors should yield the best solution
possible.
CONNECTIONS
USING THE 115sA/118sA IN A SYSTEM
SETUP SUGGESTIONS
4