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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
• Compact design allows stacking
with other S-series systems
• Subwoofer for augmenting the
low-frequency performance of EV
stage systems
__________________
1
See Connections section.
®
inputs
1
Description
The Electro-Voice S18 is a 300-watt compact 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 systems are placed side by side and paralleled, yielding a 4-ohm load. For operation at very-lowfrequencies, 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 provides 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 wavelength. 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 minimum 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, experiences rapidly increasing cone excursion
below the box-tuning frequency . The acoustic output also decreases rapidly. Therefore,
it is necessary to protect the S18 and maximize the power output of the subwoofer by
inserting an active high-pass filter. The filter 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-
TM
Wood
, a structural material that combines
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 veneers 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 perpendicularly bonded under intense heat and pressure 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, abuseresistant carpeting provides a finish that is
both attractive and highly durable. Heavyduty metal corner protectors, firmly secured
rubber feet, recessed handles and a protective metal grille complete the picture and ensure 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 sinewave input in an anechoic chamber. No ex-
TM
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S18 Subwoofer
ternal equalization was used. Figure 1 has been
averaged and normalized to 1 watt at 1 meter.
Connections
The S18 is equipped with two parallel 1/4-inch
phone jacks. (The S18-E has two parallel
Neutrik Speakon
®
NL4MP connectors.) Another woofer can be connected in parallel by
using the other connector. Care must be taken
S18 Subwoofer
not to abuse the amplifier by connecting impedances which are too low. (See amplifier
specifications supplied by the manufacturer.)
Power-Handling Capacity
Electro-Voice components and systems are
manufactured to exacting standards, ensuring
they will hold up, not only through the most
rigorous of power tests, but also through continued use in arduous, real-life conditions. The
EIA Loudspeaker Power Rating Full-Range
(ANSI/EIA RS-426-A 1980) uses a noise
spectrum which mimics typical music and tests
the thermal and mechanical capabilities of the
components. Electro-Voice will support relevant additional standards as and when they
become available. Extreme, in-house power
tests, which push the performance boundaries
of the woofers, are also performed and passed
to ensure years of trouble-free service.
Specifically, the S18 passes ANSI/EIA RS426-A 1980 with the following values:
R
= 5.87 ohms (1.15 x RE)
SR
= 300 watts
P
E(MAX)
Test voltage = 41.96 volts rms,
83.93 volts peak (+6 dB)
The “peak” power-handling capacity of a
woofer is determined by the peak test voltage
amount. For the S18, a 84.8-volt peak test
voltage translates into 1,200-watts short-term
peak power-handling capacity. This is the
equivalent of four times the “average” powerhandling capacity, and is a peak that can be
sustained for only a few milliseconds. However, this sort of short-duration peak is very
typical in speech and music. Provided the
amplifier can reproduce the signal accurately,
without clipping, the woofer will also perform
accurately and reliably, even at these levels.
Amplifier Power Recommendations
As noted in the Power-Handling section,
above, the S18 has a random-noise power ca-
pacity of 300 watts long term (1,200 watts
peak) per ANSI/EIA RS-426-A 1980. The
following guidelines will help relate this to
an appropriate power amplifier output rating.
1. To use the S18 to full capacity, skilled
experts in sound system installation and
operation will obtain the best results if
the power amplifier is 2.0 to 4.0 times
the long-term average noise power rating of the speaker system. For the S18
this is 600 to 1,200 watts.
The caution cannot be made strongly
enough, however, that this arrangement is only for experts or those who
can discipline themselves against
“pushing” the system for ever-higher
sound levels and who can avoid “accidents” such as catastrophic feedback
or dropped microphones.
At these levels the system will fail if
pushed beyond these limits even for a
short time. It should be used by experts only or with a known signal
source such as CD’s which do not feedback or do not have unknown signals
present.
2. A more conservative, “normal” amplifier
size, which will produce audible results
nearly equal to those of the “expert” recommendation, is 1.0 to 1.4 times the
long-term average noise power rating of
the speaker. For the S18 this is 300 to
420 watts.
3. To be very conservative, one can use an
amplifier rated at 0.5 to 0.7 times the
long-term average noise power rating of
the loudspeaker. For the S18 this is 150
to 210 watts.
See Speaker Protection section.
Request P.A. Bible Addition No. Two
(“Power Handling Capacity”) for more background on these recommendations.
Service
In the unlikely event the S18 requires service, the woofer can be replaced or serviced
from the front. A service data sheet is available from Electro-Voice.
Architects' and Engineers'
Specifications
The loudspeaker shall be a compact ventedbox type. The low frequencies shall be reproduced with one 300-watt (ANSI/EIA RS426-A 1980) SG18 457-mm (18-in.) woofer.
The system will reproduce the frequencies
from 45 to 3,300 Hz. The system shall be
capable of producing average sound levels
in excess of 123 dB in the long term, and
short-term peaks of 129 dB.
The enclosure shall be constructed of blackcarpeted Road-Wood
TM
and have a metal
grille which attaches with 7 screws. The
dimensions shall be 778 mm (30.7 in.) tall,
505 mm (19.9 in.) wide, and 464 mm (18.3 in.)
deep. The system shall weigh 27.7 kg (61 lb).
Two 1/4-inch phone jack connections shall
be provided. (Two Neutrik Speakon
®
connections shall be provided on the “E” version.)
The loudspeaker system shall be the Electro-Voice S18 (or S18-E).
Uniform Limited Warranty
Electro-Voice products are guaranteed
against malfunction due to defects in materials or workmanship for a specified period,
as noted in the individual product-line
statement(s) below, or in the individual product data sheet or owner’s manual, beginning
with the date of original purchase. If such
malfunction occurs during the specified period, the product will be repaired or replaced
(at our option) without charge. The product
will be returned to the customer prepaid.
Exclusions and Limitations: The Limited
W arranty does not apply to: (a) exterior finish or appearance; (b) certain specific items
described in the individual product-line
statement(s) below, or in the individual product data sheet or owner’s manual; (c) malfunction resulting from use or operation of
the product other than as specified in the
product data sheet or owner’s manual; (d)
malfunction resulting from misuse or abuse
of the product; or (e) malfunction occurring
at any time after repairs have been made to
the product by anyone other than Mark IV
Audio Service or any of its authorized service representatives. Obtaining Warranty
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S18 Subwoofer
Service: To obtain warranty service, a customer must deliver the product, prepaid, to
Mark IV Audio Service or any of its authorized service representatives together with
proof of purchase of the product in the form
of a bill of sale or receipted invoice. A list
of authorized service representatives is available from Mark IV Audio Service at 600
Cecil Street, Buchanan, MI 49107 (800/234/
6831 or FAX 616/695/4743). Incidental
and Consequential Damages Excluded:
Product repair or replacement and return to
the customer are the only remedies provided
to the customer. Electro-Voice shall not be
liable for any incidental or consequential
Figure 1—Axial Frequency Response,
(anechoic environment, 4 volts/3.05
meters (10 feet), normalized to 1 watt/1
meter)
damages including, without limitation, injury to persons or property or loss of use.
Some states do not allow the exclusion or
limitation of incidental or consequential
damages so the above limitation or exclusion may not apply to you. Other Rights:
This warranty gives you specific legal rights,
and you may also have other rights which
vary from state to state.
Electro-V oice Speakers and Speaker Systems are guaranteed against malfunction due
to defects in materials or workmanship for a
period of five (5) years from the date of original purchase. The Limited W arranty does not
apply to burned voice coils or malfunctions
such as cone and/or coil damage resulting
from improperly designed enclosures. Electro-Voice active electronics associated with
the speaker systems are guaranteed for three
(3) years from the date of original purchase.
Additional details are included in the Uniform Limited W arranty statement.
For warranty repair, service information, or
a listing of the repair facilities nearest you,
contact the service repair department at: 616/
695-6831 or 800/685-2606.
For technical assistance, contact Technical
Support at 800/234-6831 or 616/695-6831, MF , 8:00 a.m. to 5:00 p.m. eastern standard time.
Specifications subject to change without notice.
S18 Subwoofer
Figure 2—Harmonic Distortion, 10%
Rated Power Input (30 watts), (anechoic
environment, 3.05 meters (10 feet) on
axis)
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Figure 3—Impedance Curve
S18 Subwoofer
Figure 4—Dimension Line Drawing
S18 Subwoofer
Specifications
T ypical Axial Frequency Response, Swept
Sine Wave, 4 volts at 3.05 meters (10 feet),
(anechoic environment, normalized
for 1 watt at 1 meter; see Figure 1):
60-3,300 Hz
Low-Frequency 3-dB-Down Point:
60 Hz
Usable Low-Frequency Limit (10-dBdown point):
45 Hz
Half-Space Reference Efficiency:
2.9%
Long-T erm A verage Power-Handling
Capacity per ANIS/EIA RS-426-A 1980
(see Power-Handling Capacity section):
300 watts
Maximum Woofer Acoustic Output:
9 watts
Sensitivity (SPL at 1 watt, 1 meter
input, anechoic environment, swept
sine wave, 50 to 200 Hz):
98 dB
Dispersion Angle Included by 6-dBDown Points on Polar Responses:
Essentially omnidirectional
Distortion, 0.1 Full Power Input at
100 Hz (see Figure 2),
Second Harmonic:
–30 dB, 3%
Third Harmonic:
–49 dB, 0.4%
T ransducer Complement,
SG18 18-inch woofer
Box Tuning Frequency:
48 Hz
Recommended Crossover Frequency:
200 Hz or below
Recommended Crossover Slope:
12 dB per octave, minimum
Impedance,
Nominal:
8.0 ohms
Minimum:
6.2 ohms
Input Connections:
T wo parallel 1/4-inch phone jacks
(T wo parallel Neutrik Speakon
®
NL4MP connectors on S18-E)
Enclosure Materials and Colors:
Black-carpeted Road Wood
TM
Black perforated metal grille
Enclosure Dimensions (see Figure 4),
Height:
778 mm (30.7 in.)
Width:
505 mm (19.9 in.)
Depth:
464 mm (18.3 in.)
Net Weight:
27.7 kg (61 lb)
Shipping Weight:
31.8 kg (70 lb)
SPEAKERS—Low Frequency Systems
a MARK IV company
600 Cecil Street, Buchanan, MI 49107
800/234-6831, 616/695-6831, 616/695-1304 Fax
Part Number 533657 – 9639
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