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Mutual coupling occurs when the frequency is
such that the center-to-center distance be-
tween the two woofer manifolds is less than
about one-half wavelength. When the distance
is greater than one-half wavelength, as would
occur if two T18's were widely spaced, the level
increase tends to be limited to the 3-dB power-
handling increase.
The woofer is connected using one of the
®
1
Neutrik Speakon
or
/
-inch phone jacks
4
marked "input." Electro-Voice recommends the
Neutrik NL4MPR-V connector be used in most
1
high power situations. The
/
there to provide a level of backward compatibil-
ity with lower-powered systems. A parallel
woofer can be connected using the other con-
nector. Care must be taken not to abuse the
amplifier by connecting impedances which are
too low.
CROSSOVERS AND AMPLIFIERS
To optimize performance, the T18 should be
used in conjunction with an active crossover
with a minimum slope of 12 dB per octave and
a crossover frequency in the range of 100 to
250 Hz. Due to the high efficiency of the T18,
less amplifier input is needed to achieve a given
sound output level. The high power-handling
capacity of the T18 permits the use of amplifiers
with a rating of up to 800 watts rms into 8 ohms.
SPEAKER PROTECTION
When in the vented-box mode, the SubScoop,
like all other vented systems, experiences rap-
idly increasing cone excursion below the box-
tuning frequency. The acoustic output is also
decreasing rapidly; therefore, it is sensible to
protect the T18 and maximize the power output
of the subwoofer by inserting an active 32-Hz
high-pass filter with a slope of at least 12 dB per
octave into the circuit. Such subpassband fil-
ters are found in many commercially available
crossovers and equalizers including items
manufactured by Electro-Voice.
FREQUENCY RESPONSE
The T18's axial frequency response was mea-
sured in Electro-Voice's large anechoic cham-
ber at a distance of 3 meters (10 feet) with a
swept sine-wave input. Figure 1 has been aver-
aged and corrected for 1 watt at 1 meter.
ENCLOSURE CONSTRUCTION
Intended to be used as a portable speaker
system, the T18 is ruggedly constructed of
3
/
-inch void-free plywood. All joints are dado
4
cut, and the cabinet is finished with a densely-
woven, abuse-resistant carpet that is both at-
tractive and highly durable. A full-length steel
grille protects the woofer from damage. Large,
heavy-duty metal corner protectors, firmly se-
cured rubber feet, and recessed handles com-
plete the picture, ensuring that the T18 speaker
system is ideally suited for a long and reliable
life on the road.
T18 CONNECTIONS
The T18 is equipped with two paralleled Neutrik
®
Speakon
NL4MPR-V connectors, selected for
their ability to reliably deliver to the speaker
components the high currents delivered by
high-wattage power amplifiers. An NL4FC mat-
ing connector is supplied. The NL4FC is a four-
pin connector, and Figure 5 shows how the
usual two-conductor speaker cable should be
wired to pins 1+ and 1– of the connector. Two
typical connectors at the power amplifier end of
the cable are shown: banana and
plugs. (The banana plug provides the more
reliable connection.)
Note also that Neutrik Speakon
nectors and wiring accessories are available
from Pro Co Sound, Inc., and Whirlwind Music
Distributors, Inc. To find your local Pro Co,
Whirlwind or Neutrik dealer, contact:
-inch jacks are
4
Pro Co Sound, Inc.
135 E. Kalamazoo Ave.
Kalamazoo, MI 49007
616/388-9675
Whirlwind Music Distributors, Inc.
P.O. Box 1075
Rochester, NY 14603
716/663-8820
Neutrik USA, Inc.
195-S3 Lehigh Ave.
Lakewood, NJ 08701
908/901-9488
USE WITH SATELLITE
SPEAKER SYSTEMS
3
The 1
/
8
the T18 can be used with any length of standard
3
1
/
-in. tube. Care should be taken to ensure
8
that the T18 is used on a flat and level surface.
Electro-Voice strongly recommends that the
TM
top of the satellite speaker be no more than 8
feet (244 cm) above the ground and weigh no
more than 75 pounds (34 kg). It is the respon-
sibility of the user to ensure that the system is
safe and stable. Do not use where the system
can be easily knocked over.
SERVICE
In the unlikely event the T18 requires service,
the woofer can be replaced or serviced from the
front. A service data sheet is available from
Electro-Voice.
POWER-HANDLING TEST
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 contin-
ued use in arduous, real-life conditions. The
EIA Loudspeaker Power Rating Full Range
(ANSI/EIA RS-426-A 1980) uses a noise spec-
trum which mimics typical music and tests the
thermal and mechanical capabilities of the com-
ponents. 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 woof-
ers, are also performed and passed to ensure
years of trouble-free service.
Specifically, the T18 passes ANSI/EIA
RS-426-A 1980 with the following values:
R
SR
P
E(MAX)
Test voltage = 52.4 volts rms,
1
/
-inch phone
4
®
cables, con-
-in. stand mount in the top surface of
= 6.9 ohms (1.15 x R
)
E
= 400 watts
104.8 volts peak
The "peak" power-handling capacity of a woofer
is determined by the peak test voltage amount.
For the T18, a 104.8-volt peak test voltage
translates into 1,600-watts short-term peak
power-handling capacity. This is the equivalent
of four times the "average" power-handling
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 repro-
duce the signal accurately, without clipping, the
woofer will also perform accurately and reliably,
even at these levels.
ARCHITECTS' AND ENGINEERS'
SPECIFICATIONS
The loudspeaker shall be a horn-loaded type.
The low frequencies shall be reproduced with a
400-watt (ANSI/EIA RS-426-A 1980) DL18MT
46-cm (18-in.) woofer. The system will repro-
duce the frequencies from 33 to 250 Hz. The
system shall be capable of producing average
sound levels in excess of 126 dB in the long
term, and short-term peaks of 132 dB.
The enclosure shall be constructed of black,
carpeted, multilayer plywood and have a metal
grille which attaches with six screws. The di-
mensions shall be 83.3 cm (32.8 in.) tall, 63.0
cm (24.8 in.) wide and 60.9 cm (24.0 in.) deep.
The system shall weigh 49.4 kg (109 lb). Neu-
1
trik Speakon
®
and
/
-inch jack connections
4
shall be provided.
3
A 1
/
-in. stand mount capable of supporting 75
8
pounds (34 kg) will be provided in the top
surface of the T18 enclosure.
The loudspeaker system shall be the Electro-
Voice T18 subwoofer.
UNIFORM LIMITED WARRANTY
Electro-Voice products are guaranteed against
malfunction due to defects in materials or work-
manship 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 pre-
paid. Exclusions and Limitations: The Lim-
ited Warranty 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 re-
sulting from misuse or abuse of the product; or
(e) malfunction occurring at any time after re-
pairs have been made to the product by anyone
other than Electro-Voice or any of its authorized
service representatives. Obtaining Warranty
Service: To obtain warranty service, a cus-
tomer must deliver the product, prepaid, to
Electro-Voice 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
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