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SPECIFICATIONS
Frequency Response, 10 Feet on Axis,
Swept 1/3 Octave. Half Space Anechoic
Environment (see Figure 1):
65-20,CX)0 Hz
Low-Frequency 3-dB-Down Point:
65 Hz
Usable Low-Frequency Limit
(10-dB-down point):
47 Hz
Half-Space Reference Efficiency:
4.5%
Long-Term Average Power Handling
Capacity per EIA Standard RS-426A
(see Power Handling Capacity section):
300 watts
Maximum Woofer Acoustic Output:
135 watts
Sound Pressure Level at 1 Meter.
1 Watt Input. Anechoic Environment,
Band-Limited Pink Noise Signal.
300 to 2.000 Hz:
102 dB
Dispersion Angle Included by 6-dB-Down
Points on Polar Responses. Indicated One-
Third Octave Bands of Pink Noise.
250-20.000 Hz Horizontal
(see Figure 3):
106^ ±60®
5,000-20,000 Hz Vertical
(see Figure 3):
50 ® ± 11 ®
Directivity Factor Rq (01.800-16,000
Hz Median (see Figure 41:
135 (4-4.75,-8.75)
Directivity Index Dj, 800-16,000 Hz
Median (see Figure 4):
125 dB (405 dB. -5.5 dB)
Distortion. 0.1 Full Power Input
Second Harmonic,
100 Hz: 0.5%
1000 Hz: 4%
10,000 Hz: 11%
Third Harmonic,
100 Hz: 05%
1000 Hz: 2%
10,000 Hz: 3.5%
Distortion, 0.01 Full Power Input
Second Harmonic,
100 Hz: <0.5%
1000 Hz: 15%
10,000 Hz: 4%
Third Harmonic.
100 Hz: <05%
1000 Hz: 1%
10,000 Hz: <1%
Transducer Complement,
High-Frequency:
One-inch titanium diaphragm driver
90° X 40® constant-directivity horn
Low-Frequency:
EVX-15
Box Tuning Frequency:
55 Hz
Crossover Frequency:
1500 Hz
Crossover Slope:
12 dB per octave
Impedance,
Nominal:
8 ohms
Minimum:
5.3 ohms
Input Connections:
Parallel 1/4 in. phone jacks (allows
paralleling of multiple speakers)
Enclosure Materials and Colors:
Black carpet covered Road-Wood'^
Dimensions:
55.9 cm (22 in.) high
57.1 cm (22.5 in.) wide
70.8 cm (27.9 in.) deep
Net Weight:
34.2 kg (75.2 lb)
Shipping Weight:
36.9 kg (81.2 lb)
DESCRIPTION
The Electro-Voice FM-1502 is a 300
watt, two-way, high-efficiency,
constant-directivity stage monitor.
Possible system orientations are at
35°, 45° or perpendicular to the floor.
It 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
articulate high quality sound.
The enclosure is constructed of Road-
Wood'~. a structural material made of
layered and selectively oriented hard¬
wood strands. The covering is abuse-
resistant black carpeting.
The high-frequency section of the
FM-1502 utilizes a die cast 90° x 40°
constant-directivity horn, driven by a
one-inch throat, wide-bandwidth,
titanium diaphragm driver. This driver
uses a unique convex drive Time Path’*'
phasing plug structure (patent pending)
for smooth and extended high-
frequency performance.
The bass section of the FM-1502 is
designed using Thiele-Small parameters
for efficient performance to below
65 Hz. The 15-inch woofer used in the
system is an EVX-15 unit featuring
beryllium copper lead wires and an
extended length, edgewound voice coil
further protected by the unique EV
Thermo Inductive Ring (TIR’^). The
part of the magnetic structure adjacent
to the coil is insulated, using the
exclusive EV PROTEF’** process. The
coil is driven by a massive (16 lb)
magnetic structure.
200 Hz
315 Hz
630 Hz
BEAMWIDTH
IN 160
DEGREES
{-6 dB)
63
HORIZONTAL O
VERTICAL A
HORIZONTAL
800 Hz -
1,250 Hz-
2,000 Hz - -
3,150 Hz —
5,000 Hz —
8,000 Hz -
VERTICAL
15 dB per Division)
FIGURE 2 — Polar Response (1/3 octave pink noise
4 volts/10 feet)
8 H S S Sdg
g g § §§g§ii I H i I
neoueNCY in hcrtz
FIGURE 3 — Beamwidth vs Frequency
Whole Space (anechoic)
10,000 Hz
16,000 Hz
20,000 Hz
DIRECTIVITY
FACTOR
Re (Q)
NUMBERS INDICATE | | I I; 1 1
SPECIFIC Re VALUES ~| I M | i > I
—I .[|i|i
DIRECTIVITY
INDEX
Dj (dB)
« 8 §588882 g g 8S§3§§?
? ® 5 5
FREQUENCY IN HERTZ
FIGURE 4 — Directivity vs Frequency
Whole Space (anechoic)
CONSTANT-DIRECTIVITY SPEAKER
SYSTEM
The crossover frequency and speaker
component geometries have been
selected so that the directional charac*
teristics of the woofer and constant-
directivity horn match at the crossover
frequency (approximately 90° circular
coverage patterns for each) to create a
special system type — the constant-
directivity system. At higher frequencies
the horizontal coverage pattern remains
constant and the vertical pattern
smoothly transitions to a 40° to 50°
angle above 5000 Hz Response within
the 90° X 40° rated coverage angle is
uniform, which means dependable
audience coverage without "hot spots"
or dead zones at certain frequencies.
The 90° X 40° dispersion characteristic
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 transducers also
eliminates response irregularities caused
by diffraction off nearby enclosure
edges and. in combination with an
essentially flat on-axis frequency
response, produces a total acoustic
power output that is uniform with
frequency.
ENCLOSURE CONSTRUCTION
The FM-1502 enclosure utilizes a
structural material that combines the
strength of high-quality plywood with
the density and acoustic damping of
particle board without brittleness.
Road-Wood”* uses the same principle of
crossbanding veneers, as in plywood, in
order to achieve its very high rigidity. A
tough liquid-phenolic resin is blended
with long, narrow strands of hardwood.
Alternate layers are perpendicularly
bonded under intense heat and pressure
to form panels of superior uniformity.
Unlike many grades of plywood Road-
Wood is dimensionally stable, water
resistant and free from voids.
A combination of dado cut joints, tough
adhesives and proper bracing ensure a
sonically dead enclosure free from panel
resonances.
The densely woven, industrial grade,
abuse-resistant carpeting provides a
finish that is both attractive and highly
durable. Large heavy-duty metal corner
protectors, firmly secured rubber feet
and recessed handles complete the
picture and ensure that the FM-1502
speaker system is ideally suited to a long
and reliable life "on the road."
FREQUENCY RESPONSE
The combination of a 15-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, using a 4-volt
input in an anechoic chamber, and was
measured using swept 1/3 octave. No
external equalization was used.
DIRECTIVITY
A unique feature of the FM-1502 is the
constant-directivity dispersion provided
by the 90° x 40° horn. The polar
response of the system at selected 1 /3-
octave bandwidths is shown in Figure 2.
These polar responses were measured in
an anechoic environment at 10 feet
using 1/3-octave pink noise inputs. The
frequencies selected are fully represent¬
ative of the polar response of the
system utilizing the complete 1/3-octave
polar data is shown in Figure 3. Rq (Q)
and directivity index (Dj) are plotted in
Figure 4.
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 conditions. First, we use a
random noise input signal because it
contains many frequencies
simultaneously, just like real voice or
instrument program. Second, our signal
contains more energy 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 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 actual
program. The long-term average level
stresses the speaker thermally (heat).
The instantaneous peaks test mechanical
reliability (cone and diaphragm
excursion). Note that the sine wave test
signals sometimes used have a much less
demanding peak value relative to their
average level. In actual use. long-term
average levels exist from several seconds
on up. but we apply the long-term
average for several hours, adding
another extra measure of reliability.
Specifically, the FM-1502 is designed
to withstand the power test described in
the revised EIA Standard RS-426A. The
El A test sp^rum is applied for eight
hours. To obtain the spectrum, the
output of a white noise generator (white
noise is a particular type of random
noise with equal energy per bandwidth
in Hz) is fed to a shaping filter with
6-dB-per octave slopes below 40 Hz and
above 318 Hz. When measured with the
usual constant-percentage bandwidth
analyzer (one-third octave), this shaping
filter produces a spectrum whose
3-dB-down points are at 100 Hz and
1200 Hz with a 3-dB-per octave slope
above 1200 Hz. This shaped signal is
sent to the power amplifier with the
continuous power set at 300 watts into
the 6.4 ohms EIA equivalent
impedance, (43.8 volts true RMS).
Amplifier clipping sets instantaneous
peaks at 6 dB above the continuous
power, or 1200 watts peak (87.6 volts
peak). This procedure provides a
rigorous test of both thermal and
mechanical failure modes
GRILLE REMOVAL
The grille assembly of the FM-1502 is
fastened to the enclosure using four
sturdy dual-lock fasteners. The grille
assembly can be removed quickly and
easily, allowing access to the drivers by
firmly pulling on the two black
polyester ribbon loops provided.
WARRANTY (Limited) -
Electro-Voice Music Loudspeaker
Systems and Accessories are guaranteed
for five years from date of original
purchase against malfunction due to
defects in workmanship and materials.
If such malfunction occurs, unit will be
repaired or replaced (at our option)
without charge for materials or labor if
delivered prepaid to the proper
Electro-Voice service facility. Unit will
be returned prepaid. Warranty does not
cover finish or appearance items or
malfunction due to abuse or operation
at other than specified conditions.
Repair by other than Electro-Voice or
its authorized service agencies will
void this guarantee.
For shipping address and instructions on
return of Electro-Voice products for
repair and locations of authorized
service agencies, please write; Service
Department, Electro-Voice, Inc., 600
Cecil Street, Buchanan, Michigan 49107
(Phone: 616/695-6831) or
Electro-Voice West, 8234 Doe Avenue
Visalia, California 93277
(Phone: 209/651-7777).
Electro-Voice also maintains complete
facilities for non-warranty service.
Service and repair address for this
product: Electro-Voice, Inc., 600 Cecil
St., Buchanan, Michigan 49107.
Specifications subject to change
without notice.
® Gulton Industries, Inc. 1984
aGulbon coMP.Nv ELECTRO-VOICE, Inc.,
Part Number 530400 — 403
600 CECIL ST., BUCHANAN, MICH. 49107
manufacturing plants at ■ BUCHANAN, MICH. ■ NEWPORT, TENN ■ SEVIERVILLE, TENN. ■ GANANOQUE. ONT. ■ LITHO IN U.S.A.