EVX-180B
18-Inch Low-Frequency
Reproducer
• Exceptionally resistant to long-
term failure in real-world low-bass
applications
• Utilizes findings about failure
modes not revealed in normal
high-power testing
• 1,000 watts continuous program
• Advanced, HeatWick
TM
design
“wicks” away heat from the voice
coil
• Long, 4-inch voice coil has nearly
twice the surface area of any other
woofer, virtually eliminating power
compression
• Ribbed, Kevlar
®
fiber composite
cone resists collapse
1
Description
The EVX-180B low-frequency transducer is
designed for professional sound reinforce-
ment or studio monitoring applications that
require maximum output with low distortion.
The EVX-180B woofer provides unprec-
edented power capacity, linearity and excur-
sion, made possible by the HeatWick
TM
to-
tal-thermal-engineering design. The propri-
etary HeatWick design actually “wicks” heat
away from the voice coil, significantly in-
creasing power handling and long-term reli-
ability. A special frame extension and elon-
gated pole piece provide a metal surface with
close proximity to the entire length of the
voice coil, providing a major heat-transfer
path. Also, the 100-mm (4-in.) diameter
voice coil is longer than conventional me-
dium-efficiency woofers to give additional
power handling and virtually eliminate dy-
namic-range power compression.
Additionally, a Flux Demodulation Device
(FDD
TM
) reduces distortion in the critical mid
band by providing a “short circuit” effect to
prevent amplifier-signal modulation of the
static magnetic field.
A ribbed, Kevlar
®
fiber composite cone with
an extremely high stiffness-to-weight
ratio and exceptional strength gives the
EVX-180B increased resistance to cone col-
lapse and deformation, without sacrificing
efficiency.
1
A rubber mounting flange
gasket provides a reusable seal for front or
rear mounting, completely surrounding the
frame flange.
Directional Performance
The directional characteristics of the
EVX-180B in the TL3512 256-liter (9-ft
3
)
vented enclosure were measured by running
a set of polar responses in EV’s large
anechoic chamber. The test signal was oc-
tave-band-limited pseudo-random pink noise
centered at the ISO standard frequencies.
The curves show horizontal (side-to-side)
dispersion when the enclosure’s long axis is
vertical. The vertical (up-and-down) polar
responses deviate only slightly from the hori-
zontal responses due to box geometry. Typi-
cal data is provided in Figures 3 and 4, which
indicate 6-dB-down beamwidth versus fre-
quency and directivity factor, respectively,
for an EVX-180B in the TL3512 enclosure.
Power-Handling Test
To our knowledge, Electro-Voice was the
first U.S. manufacturer to develop and pub-
lish a power test closely related to real-life
conditions. First, we use a random noise in-
put signal because it contains many frequen-
cies simultaneously, just like real voice or
instrument program. Second, our signal con-
tains more energy at extremely high and low
frequencies than typical actual program, add-
ing an extra measure of reliability. Third, the
test signal includes not only the overall
“long-term average” or “continuous” level—
which our ears interpret as loudness—but
also short-duration peaks which are many
times higher than the average, just like ac-
tual program. The long-term average level
stresses the speaker thermally (heat). The
instantaneous peaks test mechanical reliabil-
ity (cone and diaphragm excursion).
Specifically, the EVX-180B is designed to
withstand the power test described in EIA
Standard RS-426A. The EIA test spectrum
is applied for eight hours. To obtain the spec-
trum, the output of a white-noise generator
(white noise is a particular type of random
__________
1. Kevlar
®
is a registered trademarks of DuPont.
