Electro-Voice S18 Specifications

Description
The Electro-Voice S18 is a 300-watt com-
pact subwoofer loudspeaker system that has
been designed specifically to complement
the Electro-Voice S-Series stage systems. It
provides solid low-frequency performance
to 45 Hz for a variety of applications. The
enclosure venting provides control of the
woofer's excursion at the lowest frequencies
of the subwoofer's output. Excursion is
minimized at 48 Hz, with the majority of the
output coming from the vents.
Use In Multiples
The S18 may be used in multiples to increase
acoustic output. A 6-dB increase in maximum
acoustic output occurs when two speaker sys-
tems are placed side by side and paralleled, yield-
ing a 4-ohm load. For operation at very-low-
frequencies, the woofer cones "mutually couple,"
acting as one system with twice the effective cone
area at very-low frequencies to provide 3-dB more
output, while the doubled power capacity pro-
vides the potential for an additional 3-dB gain in
maximum acoustic output.
Mutual coupling occurs when the frequency is
such that the center-to-center distance between
the two woofers is less than about one-half wave-
length. When the distance is greater than one-
half wavelength, as would occur if two S18's
were widely spaced, the level increase is limited
to the 3-dB power capacity increase.
Crossover
Although the S18 can be used without an active
crossover to a full-range system, for optimum
performance, an active crossover with a mini-
mum slope of 12-dB-per-octave and a crossover
frequency of 200 Hz or below is recommended.
Speaker Protection
The S18, like all other vented systems, ex-
periences rapidly increasing cone excursion
below the box-tuning frequency. The acous-
tic output also decreases rapidly. Therefore,
it is necessary to protect the S18 and maxi-
mize the power output of the subwoofer by
inserting an active high-pass filter. The fil-
ter should be in the 30- to 40-Hz range with
a typical value of 32-Hz and a slope of at
least 12 dB per octave. Such subpassband
filters are found in many crossovers and
equalizers manufactured by Electro-Voice,
as well as other commercially available
equipment.
Enclosure Construction
The S18 enclosure is constructed of Road-
Wood TM , a structural material that combines
S18
Subwoofer
• SG18 18-inch woofer for remark-
able, extended low-frequency
output
• 300-watt long-term rms power
capacity
• Roadworthy enclosure with metal
corners, a metal grille and a
durable black carpet finish
• Dual 1/4-inch phone jack or dual
Neutrik Speakon ® inputs
• Compact design allows stacking
with other S-series systems
• Subwoofer for augmenting the
low-frequency performance of EV
stage systems
__________________
1
See Connections section.
the strength of high-quality plywood with the
density and acoustic damping of particle
board, without brittleness. Road-Wood
uses the same principle of crossbanding ve-
neers as in plywood, in order to achieve its
very high rigidity. A tough liquid-phenolic
resin is blended with long, narrow strands
of hard-wood. Alternate layers are perpen-
dicularly bonded under intense heat and pres-
sure to form panels of superior uniformity.
Unlike many grades of plywood, Road-
TM
Wood is dimensionally stable, water-resis-
tant and free from voids.
A combination of dado cut joints and tough
adhesives ensure a sonically dead enclosure
free from panel resonances.
The densely-woven, industrial-grade, abuse-
resistant carpeting provides a finish that is
both attractive and highly durable. Heavy-
duty metal corner protectors, firmly secured
rubber feet, recessed handles and a protec-
tive metal grille complete the picture and en-
sure that the S18 speaker system is ideally
suited to a long and reliable life on the road.
Frequency Response
The S18's axial frequency response is shown
in Figure 1. This response was measured at
3.05 meters (10 feet), using a 4-volt swept sine-
wave input in an anechoic chamber. No ex-
1
TM