Electro-Voice Sx200 - Description of Speaker System; Constant-Directivity Horn; System Controller and Bass Modules; High-Frequency Driver

DESCRIPTION
The Electro-Voice Sx200 is a 300-watt, 12-inch
two-way, high-efficiency, constant-directivity
portable speaker system. Through the exten¬
sive use of computer-aided design and model¬
ing, Electro-Voice engineers have developed a
state-of-the-art professional loudspeaker sys¬
tem.
The high-frequency section of the Sx200 ultilizes
a molded-in, 65° x 65°constant-directivity horn.
This unique pattern contributes to high intelligi¬
bility. Vocals sound natural yet “cut through" in
reverberant, noisy rooms. In addition, the
coverage pattern is unusually uniform over its
range of operation. Sound quality off axis is
very well maintained, even at 45° off axis (a 90°
total coverage angle), well beyond the rated
coverage angle. The horn's unique, Varipath ™
throat geometry' helps direct driver output to
the corners of the room, points of coverage not
described in the usual specifications of hori¬
zontal and vertical coverage angles, and parts
of the audience that typically do not receive the
strongest coverage.
One of the many other unique features of the
Sx200 is the cabinet. Constructed of high-
impact polypropylene structural foam, it pro¬
vides a stiff and extremely durable enclosure.
Molded into the cabinet are an integral carrying
handle and a stand socket for mounting on
l 3 /«-lnch stands such as the Electro-Voice
model 10C8K. Rubber feet that are attached to
the bottom of the cabinet and mating sockets
that are molded into the top provide a means of
stacking systems. The trapezoidal-shaped cabi¬
net, in combination with the uniform, 65° x 65°
directivity characteristics, make the Sx200 ideal
for use alone or in arrays.
Two feet are supplied with the Sx200 which
allow the system to be used horizontally as a
stage monitor. The feet are used by inserting
them into the holes at the rear of the cabinet
The “O" rings on the feet allow the feet to be
removed many times without wear. T wo screws
are provided to position the feet permanently, if
desired.
In situations requiring additional bass output,
the Sx200 can be used in combination with the
Electro-Voice Xp200A system controller. The
Xp200A includes a low-frequency enhance¬
ment circuit that is tailored to match the low-
frequency characteristics of the Sx200. Up to
12 dB of additional bass output can be obtained
from the system when used with the Xp200A
system controller. The amount of low-frequency
enhancement can be adjusted to suit the user's
personal preference.
For the most demanding situations, two bass-
module models are available to complement
the Sx200: the Electro-Voice Sb120
nonpowered bass module and the Electro-
Voice Sb120a powered bass module. Both
bass modules were designed to be used with
the Sx200 and are constructed in similar struc¬
tural foam enclosures. The Sb120a includes a
400-watt power amplifier that is built into the
speaker cabinet. The Xp200A system control¬
ler provides a sub-woofer output that is a
crossed-over sum of the left and right chan¬
nels.
The Sx200's high-frequency horn is driven by
the DH2010 A one-inch-throat, wide-bandwidth,
titanium-diaphragm driver. The DH20l0Auses
a unique, convex-drive Time Path ™ phasing
plug structure (U.S. Patent #4,525,604) for
smooth and extended high-frequency perfor-
' Patent applied lor.
mance. The voice coil is coupled to the dia¬
phragm with EV's exclusive Resonant Drive ™
technology. This increases and smooths the
high-frequency response and reduces the
amount of Internal equalization required for flat
frequency response. Driver output extends to
25,000 Hz.
A self-resetting high-frequency protection cir¬
cuit, EV's PRO ™ circuit, is Included with the
Sx200 to prevent against accidental overdrive
and improve system reliability. If the input
power to the high-frequency driver exceeds the
nominal rating, the protection circuit is acti¬
vated and reduces the power delivered to the
driver by 6 dB. The system will remain in this
mode of operation until the input power is
reduced to a safe level.
The bass section of the Sx200 is designed
using Thiele-Small parameters for efficient
performance to below 80 Hz. The woofer is a
12-inch Pro-Line unit featuring beryllium cop¬
per lead wires, a low-mass, edge-wound voice
coil and high-temperature materials The part
of the magnetic structure adjacent to the coil is
insulated using the exclusive EV PROTEF ™
process (U.S. Patent #4,547,632). The coil is
driven by a 16-lb magnetic structure. The sys¬
tem combines professional-quality components,
arranged in a time-coherent vertical array, with
an unusually durable Thiele-Small-aligned
vented enclosure. The result is clear and ar¬
ticulate, high-quality sound.
FREQUENCY RESPONSE
The combination of a 12-inch woofer, wide-
bandwidth high-frequency driver and an equal¬
ized crossover results in the wide and smooth
overall response shown in Figure 1. This re¬
sponse was measured at 10 feet, using a 4-volt
input in an anechoic chamber, and was mea¬
sured using a swept sine-wave input. No exter¬
nal equalization was used. Figure 1 has been
averaged and corrected for 1 watt at 1 meter.
CONSTANT-DIRECTIVITY
SPEAKER SYSTEM
The crossover frequency and speaker compo¬
nent geometries have been selected so that
the directional characteristics of the woofer and
constant-directivity horn match at the cross¬
over frequency to create a special system
type—the constant-directivity system. Re¬
sponse within the 65° rated coverage angle is
uniform, which means dependable audience
coverage without “hot spots' or dead zones at
certain frequencies. The 65° dispersion char¬
acteristic also helps avoid early reflections
from nearby floor or side-wall surfaces which
could degrade performance. The controlled
directivity of the high- and low-frequency trans¬
ducers iso eliminates response irregularities
caused by diffraction off nearby enclosure edges
and, in combination with an essentially fiat on-
axis frequency response, produces a total
acoustic power output that is uniform with
frequency.
DIRECTIVITY
A unique feature of the Sx200 is the constant-
directivity dispersion provided by the 65° x 65°
horn. The polar response of the system at
selected one-third-octave bandwidths is shown
in Figure 2. These polar responses were mea¬
sured in an anechoic environment at 10 feet
using one-third-octave pink-noise inputs. The
frequencies selected are fully representative of
the polar response of the system. Beamwidth
of the system utilizing the complete one-third-
octave polar data is shown in Figure 3. R, and
directivity index (D,) are plotted in Figure 4.
SUSPENDING Sx200 ENCLOSURES
WARNING: Suspending any object is po¬
tentially dangerous and should only be at¬
tempted by individuals who have a thor¬
ough knowledge of the techniques and regu¬
lations of rigging objects overhead. Electro-
Voice strongly recommends that the Sx200
be suspended taking into account all cur¬
rent national, federal, state and local regula¬
tions. It is the responsibility of the installer
to ensure the Sx200 is safely installed in
accordance with all such regulations. If the
Sx200 is suspended, Electro- Voice strongly
recommends that the system be inspected
at least once a year. If any sign of weakness
or damage is detected , remedial action
should be taken immediately.
A manual entitled Suspending System 200 ™
Loudspeakers is included with every Sx200
system. It gives a summary of the suspension
kits available and an idea of how each kit is
used. A brief overview, which illustrates some
approaches for single and multiple suspen¬
sion, is given here for the benefit of the system
designer. Please refer to individual suspension
kit engineering data sheets for full details and
safety information.
The first approach is to suspend an individual
Sx200 enclosure The four metric M8 x 1.25
''inserts (see Figure 5) which are built into the
enclosure allow the system to be suspended
using eyebolts (Mb 100 Accessory Kit). Typi¬
cally it will he necessary to attach twn cables to
the top eyebolt and 'pull up" on the rear. The
Mb200 bracket (see Figure 7) encompasses
the top and bottom of the enclosure and has
additional features to make suspending the
Sx200 easier and more flexible.Electro-Voice
recommends the use of the Mb200 in all but the
simplest situations. The Mb200 has supple¬
mentary holes to allow the Sx200 to be at¬
tached to a wall or ceiling and aimed at an
audience.
The Mb200 Installation Kit also allows the use
of OmniMount® Series 100 mounting hardware
by providing three-hole-pattern groups com¬
patible with these support systems When
OmniMount® Series 100 mounting hardware is
specified, the Mb200 Installation Kit must first
be attached to the speaker enclosure.
The second approach is to suspend multiple
Sx200 enclosures. The Sx200 enclosure is not
designed to suspend multiple enclosures from
itself. If an “array" is required, then multiple
Mb200's must be used Arrays may be con¬
structed vertically by “daisy chaining" two
Mb200's from each other. The Mb30Q array
bracket allows the easy and secure construc¬
tion of horizontal arrays, using Mb200's to
support the enclosure.
POWER-HANDLING CAPACITY
To our knowledge, Electro-Voice was the first
U.S. manufacturer to develop and publish a
power test closely related to real-life condi¬
tions. First, we use a random-noise input signal
because it contains many frequencies simulta¬
neously, just like real voice or instrument pro¬
gram. Second, our signal contains more en¬
ergy at extremely high and low frequencies
than typical actual program, adding an extra
measure of reliability. Third, the test signal
includes not only the overall “long-term aver¬
age" or “continuous" level—which our ears
interpret as loudness—but also short-duration
peaks which are many times higher than the
average, just like actual program. The long¬
term average level stresses the speaker ther¬
mally (heat). The instantaneous peaks test
mechanical reliability (cone and diaphragm
excursion). Note that the sine-wave test sig-