Sx300a 300-Watt Powered Two-Way Compact Speaker System
Sx300a 300-Watt Powered Two-Way Compact Speaker System
that is built into the speaker cabinet. The
Xp200A system controller provides a sub-
woofer output that is a crossed-over sum of
the left and right channels.
The Sx300a’s high-frequency horn is driven
by the DH2010A one-inch-throat, wide-
bandwidth, titanium-diaphragm driver. The
DH2010A uses a unique, convex-drive
Time Path
TM
phasing plug structure (U.S.
Patent #4,525,604) for smooth and ex-
tended high-frequency performance. The
voice coil is coupled to the diaphragm with
EV’s exclusive Resonant Drive
TM
technol-
ogy. This increases and smooths the high-
frequency response and reduces the amount
of internal equalization required for flat fre-
quency response. Driver output extends to
25,000 Hz.
The bass section of the Sx300a is designed
using Thiele-Small parameters for efficient
performance to below 80 Hz. The woofer is
a 12-inch unit featuring beryllium copper
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
TM
process (U.S. Patent
#4,547,632). The coil is driven by a 16-lb
magnetic structure. The system combines
professional-quality components, arranged in
a time-coherent vertical array, with an un-
usually durable Thiele-Small-aligned vented
enclosure. The result is clear and articulate,
high-quality sound.
Ring-Mode Decoupling (RMD
TM
)
The Sx300a controls both acoustical and me-
chanical ring modes to provide dramatically
increased intelligibility, using techniques
learned from the development of the Elec-
tro-Voice X-Array™ concert speakers.
There is much less coloration of the sound
from resonating sources, leaving only the in-
tended sound to be heard by the audience.
Frequency Response
The combination of a 12-inch woofer, wide-
bandwidth high-frequency driver and an
equalized crossover results in the wide and
smooth overall response shown in Figure 1.
This response was measured at 10 feet, us-
ing a 4-volt input in an anechoic chamber,
and was measured using a swept sine-wave
input. No external 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 com-
ponent geometries have been selected so that
the directional characteristics of the woofer
and constant-directivity horn match at the
crossover frequency to create a special sys-
tem type—the constant-directivity system.
Response within the 65° rated coverage angle
is uniform, which means dependable audi-
ence coverage without “hot spots” or dead
zones at certain frequencies. The 65° disper-
sion characteristic also helps avoid early re-
flections from nearby floor or side-wall sur-
faces which could degrade performance. The
controlled directivity of the high- and low-
frequency transducers also eliminates re-
sponse irregularities caused by diffraction off
nearby enclosure edges and, in combination
with an essentially flat on-axis frequency re-
sponse, produces a total acoustic power out-
put that is uniform with frequency.
Directivity
A unique feature of the Sx300a is the con-
stant-directivity dispersion provided by the
65° x 65° horn. The polar response of the
system at selected one-third-octave band-
widths is shown in Figure 4. These polar re-
sponses were measured in an anechoic envi-
ronment 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 uti-
lizing the complete one-third-octave polar
data is shown in Figure 5. R
q
and directivity
index (D
i
) are plotted in Figure 6.
Xp200A Electronic System Controller
The optional Xp200A electronic system con-
troller complements the characteristics of the
Sx300a. Its mono-summed subwoofer out-
puts provide additional crossover and infra-
sonic protection. 24-dB-per-octave filters roll
off response below 37 Hz and above 100 Hz.
The Xp200A also includes a special low-fre-
quency profile circuit that enhances the per-
formance of the SX300a. The amount of
enhancement can be adjusted to suit the
user’s personal preference.
Electronics Operation and Installation
To facilitate operation and installation,
Sx300a back-panel detail is shown in Fig-
ure 3.
Precautions
Please read the entire data sheet before con-
necting the Sx300a to your system. For op-
timum performance, observe the following
precautions:
1. Keep the AC power switch off while
making connections.
2. Be certain that plugs and jacks are tightly
mated. Loose connections cause hum,
noise or intermittences that could dam-
age your speakers.
3. Use the proper, high-quality shielded
cables in your entire system. Low-capaci-
tance cable is preferred.
4. Turn on the mixer, EQ and effects first.
Wait eight to ten seconds, then turn on
the Sx300a. This prevents any transient
“pop” which could damage a loud
speaker.
5. Always begin with the mixer master fad-
ers at minimum. Wait a few seconds to
turn up the volume.
6. Use restraint in operating controls. Move
them slowly. Rapid movements could
damage speakers through accidental am-
plifier clipping.
7. To prevent fire or electrical shock, do not
expose the Sx300a to rain or excess mois-
ture.
8. Do not be concerned when the speaker
“pops” when turned on. This is inten-
tional to indicate status and does not sig-
nify a problem.
Signal Input
The Sx300a may be driven by any line-level
signal source, balanced or unbalanced. Cau-
tion: do not connect the output of a power
amplifier to the input. Although this should
not damage the Sx300a, it is very likely to
result in distorted sound quality because the
output voltage of a power amplifier is typi-
cally high enough to severely clip the input
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