Electro-Voice FRX-940 Manual

Description
The Electro-Voice FRX-940 is a two-way,
high-efficiency, horn-loaded speaker system
designed for indoor sound reinforcement in
fixed installations such as churches, meeting
halls and auditoriums. Capable of producing
sound pressure levels (SPL) in excess of 124
dB at 1 meter, the FRX-940 will give full-
bandwidth reproduction without sacrificing
sonic quality. The FRX-940 features a
90° x 40° horn. The DH2T compression driver
provides smooth, extended response to 20 kHz
and features a titanium diaphragm and a unique
convex-drive Time Path™ phasing-plug struc-
ture (U.S Patent #4,525,604).
The optimally vented bass section of the
FRX-940 is designed using Theile-Small pa-
rameters for efficient performance to below
50 Hz and utilizes a 400-watt DL15-FRX
15-inch woofer to provide high excursion with
low coloration.
The FRX-940 is provided with a passive cross-
over which features 12-dB/octave slopes cen-
tered acoustically at 1,800 Hz and EV's self-
resetting PRO™ circuit to guard the compres-
sion driver against damage. The system can
be easily converted to be operated in the biamp
mode by removing the input-panel assembly
(eight screws) and moving the four jumpers
as indicated on the crossover. When used in
biamp mode the woofer uses pins 1+ and 1–
and the tweeter uses pins 2+ and 2–.
The enclosure is constructed from seven-ply
plywood and is available in three alternative
finishes; FRX-940 BLK (black textured paint),
FRX-940 UN (unfinished and ready to stain)
and FRX-940 WH (white textured paint).
The grille is constructed from 16-gauge
powder-coated steel and is backed with foam.
Ring-Mode Decoupling (RMD™)
The FRX-940 controls both acoustical and
mechanical ring modes to provide dramati-
cally increased intelligibility, using tech-
niques learned from the development of the
Electro-Voice X-Array™ concert speakers.
There is much less coloration of the sound
from resonating sources, leaving only the
intended sound to be heard by the audience.
Frequency Response
The FRX-940 axial frequency response was
measured in Electro-Voice's large anechoic
chamber at a distance of 10 feet with a swept
sine-wave input (see Figure 1). The response
curves show response with the passive cross-
over and with the FRX-940 in the biamped
mode with presets for the Electro-Voice
DX34A digital loudspeaker processor. On
FRX-940
High-Output,
Two-Way,Horn-Loaded
Coaxial Speaker System
• 15-inch woofer
• 90° x 40° coverage
• Vented LF horn design delivers
rated control to 500 Hz
• 400-watts long-term power capacity
• Ring-Mode Decoupling (RMD™)
• Available in black (BLK) unfin-
ished (UN) and white (WH)
• Full-range or biamp operation
with internal passive crossover
• DH2T 1-inch-exit titanium
compression driver
• Built-in L-track rigging
Axis, one watt calculated using E
meter measurement distance referred to one
meter.
Directivity
The directional characteristics of the FRX-940
were measured in Electro-Voice's large
anechoic chamber. The test signal was one-
third-octave filtered pink noise at the frequen-
cies indicated. A full spherical measurement
system was used. All directional information
was measured at 20 feet.
Figure 2 illustrates the horizontal and vertical
polar responses with the internal crossover in
the passive mode.
Figure 3 shows the horizontal and vertical
beamwidths. Beamwidth is the angle at which
the horizontal and vertical polar responses have
decreased in level by 6 dB when compared
with the axial frequency response.
Figure 4 illustrates the total directivity of the
FRX-940. The directivity factor R
relative value, at a point, of the FRX-940 out-
put when compared to an ideal spherical re-
sponse. The directivity index, D
by D = 10 log R .
θ
i 10
Power-Handling Test
Electro-Voice components and systems are
manufactured to exacting standards, ensuring
z
/Z , 3.16-
min
(Q) is the
θ
, is calculated
i