Electro-Voice 18BX Datasheet

Electro-Voice 18BX Datasheet
18-lnch Long-Throw Bass
Guitar Loudspeaker
Usable Frequency Response in a Typical
Vented 8.0-Cubic-Foot Enclosure
(1 wattJ1 meter; see Figure 1):
30-4,000 Hz
Sound Pressure Level (1 wattJ1 meter):
101 dB
Long-Term Average Power Handling
Capacity (per EIA RS-426-A 1980; see
Power Handling section):
400 watts
Nominal Impedance:
8 ohms
Voice-Coil Diameter:
63.5 mm (2.5 in.)
Thiele-Small Driver Parameters
'. (free-air resonance frequency):
31 Hz
at f.):
ES (electromagnetic
OMS (mechanical
at f.):
ars (total a at f.:
(a•• am.)
(a.. + am.) :
V (volume of air having same acoustic
. ):
as d river
623.0 liters (22.0 ft3)
7]0 (half-space reference efficiency):
Vo (peak displacement volume of
diaphragm: So x Xmax):
0.463 liters (0.0164 fP)
So (effective diaphragm area):
0.114 m2 (176.7 in.2)
X (peak linear displacement of
4.06 mm (0.16 in.)
R. (dc resistance of voice coil):
6.0 ohms ±10%
Mounting Information
(see Installation section),
Mounting Hole Diameter
(eight evenly spaced holes):
7.1 mm (0.28 in.)~etter "L" drill
Bolt Circle Diameter:
370 mm (14.56 in.)
Baffle Opening Diameter,
Front Mounting:
422 mm (16.63 in.)
Rear Mounting:
416 mm (16.38 in.)
Optional Mounting Accessory:
SMH-1 mounting hardware kit
Dimensions (see Figure 2),
Overall Diameter:
460 mm (18.10 in.)
Overall Depth:
203 mm (8.0 in.)
Net Weight:
9.9 kg (22 Ib)
Shipping Weight:
12.0 kg (26.5 Ib)
The Electro-Voice 18BX is an 18-inch speaker
designed for professional, high-level, high-quality musical instrument systems. For bass guitar
use, the 18BX can provide stronger-than-usual
output at the lowest bass tones (30-50 Hz), and
its high-frequency response is tailored for a
traditional bass sound. The 18BX incorporates
voice-coil and suspension refinements, including beryllium copper flatwire leads, that have
improved performance. Power capacity is 400
watts per EIA RS-426-A 1980. The PowerHandling section describes these ratings in
The construction of the 18BX features an overhung low-mass edge-wound voice coil on a
rugged laminated polyimide coil form, driven by
Contoured response for bass
Improved low-frequency
performance-less distortion
at low frequencies
Ideal upgrade speaker
400 watts long-term power
Edge-wound flat aluminum
wire for maximum output and
"bulletproof" reliability
101-dB sensitivity
our large, 16-lb magnetic structure. Also featured are a heavy-duty curvilinear cone and a
fatigue-resistant cone suspension. Both the
coil and magnetic structure are vented. All of
this is packaged around a rugged, eight-spoke,
diecast aluminum frame.
The 18BX may be front- or rear-mounted without an adapter. The optional SMH-1 speaker
mounting kit facilitates front mounting (see Installation section).
Replacement Use In Existing Enclosures
The 18BX will often be used to replace inferior
speakers in existing enclosures. Mechanical
and electrical characteristics are such that the
superior efficiency, sound quality and reliability
of the 18BX will be realized in virtually any
sealed, vented (bass reflex) or horn-loaded
Vented Enclosures
The most extended, lowest distortion and bestcontrolled bass performance is usually realized
in properly designed vented enclosures. In
such designs, the vent, or port, actually reproduces the lowest octave or so of bass response. The vent is driven to full acoustic
output by a relatively small motion of the speaker
cone itself, acting through the air contained
within the enclosure. The excursion of the 18BX
at these frequencies is much reduced compared to sealed or open-backed enclosures,
directly reducing harmonic distortion.
Often, in bass guitar systems, a perfectly flat
response is not as important as a controlled
response. Typical sound-reinforcement systems are "tuned," so the enclosure provides the
flattest possible response. Generally, bassguitar system performance is improved if the
enclosure is vented or tuned for roughly the
lSBX Frequency Response In Typical Enclosure
(S.O ft'), 1 WatVl Meter
Button-Head Machine Screw for Front Mounting
(not to scale)
.... ,
70" ..
lSBX Dimensions
203 mm
Connection of Two lSBX Speakers in Parallel
(net impedance is 4 ohms)
Front-Mounting Detail (not to scale)
Connection of Two lSBX Speakers in Series
(net Impedance is 16 ohms)
Connection of Four lSBX Speakers in Series/Parallel
(net impedance is S ohms)
Rear-Mounting Detail (not to scale)
'1 ....1---- SPEAKER FRAME
lowest notes that will be played through it. For
standard tuning four-string bass, a 44 Hz tuning
is recommended. The low "E" on a bass guitar
actually vibrates at 41.2 Hz, but a 44 Hz tuning
will provide a reasonable amount of vent contribution or additional output at 41.2 Hz. Similarly,
an enclosure tuning of 34 Hz is recommended
for a system that will reproduce standard fiveor six-string signals. If a four-string bass with a
"dropped-D" is used, the recommended tuning
frequency is 40 Hz. For any of the above
examples, the recommended enclosure internal volume is between five and ten cubic feet.
The larger the volume, the less equalization will
be required. An enclosure volume of eight cubic
feet is ample for most situations.
The 18BX may be front- or rear-mounted, although front mounting is preferred because of
convenience. For simple front mounting, the
convenient SMH-1 mounting accessory is recommended. Complete mounting instructions
are included with the SMH-1 . Instructions for
standard front mounting are given below. It is
important that recommended baffle openings
and mounting hole locations be followed.
Front Mounting
Front mounting requires a 422-mm (16.63-in.)
diameter cutout and a 438-mm (17.25-in.) bolt
circle. Mark the baffle opening and screw locations on the blank panel first. Drill the screw
holes before cutting the large baffle opening.
If '/4-20 screws are used, four screws are
sufficient for secure mounting of the speaker.
T-nuts are recommended for simple, secure
mounting. If T-nuts are used, the holes should
be 7.1-mm (0.281-in.) diameter (letter "L" drill) .
Apply glue to the flanges of '/4-20 long shank
T-nuts before driving into the rear of the holes.
Sealing of the front-mounted speaker is accomplished with the adhesive-backed foam gasket
segments that are included with your new 18BX.
Strip off the protective paper and apply the
gasket to the rear mounting surface of the
speaker rim, making certain that the holes in the
gasket line up with the mounting holes in the
speaker frame.
Length of the '/4-20 screws should be '/2-inch
plus the panel thickness when using T-nuts.
The screws should be button-head machine
screws to seat down in the recess of the speaker
frame gasket (see Figure 3). Screws should be
tightened evenly and securely. Maximum torque
possible with a proper size screwdriver should
be sufficient.
IMPORTANT! When front mounting, the
screw head must fit down Into the front
gasket cutout (see Figure 3).
Rear Mounting
Rear mounting requires a 416-mm (16.38-in.)
cutout with a screw circle the same diameter as
front mounting (438 mm/17.25 in.). Other comments regarding the use of T -nuts apply to rear
mounting as well.
Screw length should be 3/4 -inch plus panel
thickness if using T -nuts---1onger for standard
hex nuts. If hex nuts are used, a second nut
should be tightened against the first nut to
prevent loosening during operation. A lock
washer and flat washer are recommended between the screw head and frame (see Figure 4).
Screws should be tightened evenly, but not
excessively. Maximum torque possible with a
proper size screwdriver should be sufficient. Do
not use adhesive-back gasket segments for
rear mounting.
Custom Enclosures
If a cabinet is to be constructed from scratch,
3/4 -inch solid and jointed or marine plywood is
recommended. After construction, be certain
interior is completely free of metal filings, wood
chips, etc.
Electrical Connections
Use no. 18 or larger stranded wire to connect
the two terminals on the loudspeaker to the
amplifier output.
Frequency response was measured with the
18BX in a 8.0-cubic-foot vented enclosure,
tuned to 34 Hz, placed in an anechoic (echo less)
environment at 1 meter on axis with a 1-watt
swept sine-wave input. The frequency-response
curve is shown in Figure 1.
In musical-instrument systems, unlike soundreinforcement systems, it is advisable to use
speakers that are rated for at least as much
power as your amplifier output rating .
To our knowledge, Electro-Voice was the first
U.S. manufacturer to develop and publish a
power test closely related to real-life conditions.
Specifically, the 18BX is designed to withstand
the power test described in EIA RS-426-A
1980. The EIA test spectrum is applied for eight
hours. This shaped signal is sent to a power
amplifier with the continuous power set at 400
watts into the 6.9 ohms EIA equivalent impedance (52.5 volts true rms) . Amplifier clipping
sets instantaneous peaks at 6 dB above the
continuous power, or 1,600 watts peak (105.1
volts peak). This procedure provides a rigorous
test of both thermal and mechanical failure
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, orin
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
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 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
Electro-Voice or any of its authorized service
representatives. Obtaining Warranty Service:
To obtain warranty service, a customer 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 representatives is
available from Electro-Voice at 600 Cecil Street,
Buchanan, MI 49107 (616/695-6831 or 800/
234-6831). Incidental and Consequential
Damages Excluded: Product repairor replacement and return to the customer are the only
remedies provided to the customer. ElectroVoice shall not be liable for any incidental or
consequential 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
Electro-Voice 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 Warranty 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 Warranty
Service and repair address for this product:
Electro-Voice, Inc., 600 Cecil Street, Buchanan,
Michigan 49107 (616/695-6831 or 800/2346831).
Specifications subject to change without
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