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Accurate, smooth reproduction
44 dB SPL at 30 feet with a l-milliwatt input
101 dB SPL at 10 feet at one-half rated power input
Components: 15inch low frequency loudspeaker,
high frequency compression driver with horn/lens
assembly; the 4333A is also furnished with an ultra
high frequency transducer.
Mountable in vertical or horizontal orientation
Balance controls located behind the removable grille
Rear mounted switch for bi-amplification or full
passive crossover
Oiled Walnut or textured gray enclosure
The 4331A and 4333A Studio Monitors
The 433 1A and 4333A are rugged, powerful studio
monitors designed for mixdown and mastering control
room applications. The result of an extensive research
and development effort, they represent a refinement of
the classic JBL two-way studio monitor loudspeaker
system that has been relied on by a major segment
of the recording industry for the past 15 years.
The transducers installed in each system are iden-
tical: a newly developed 1 S-inch low frequency loud-
speaker and a wide range high frequency compression
driver equipped with a newly developed horn/lens
assembly with the addition of an ultra-high frequency
transducer in the 4333A which extends the bandwidth
to 20,000 Hz.
The network design integrates the performance of
the individual drivers, taldng into account their location
on the enclosure baffle panel and the acoustic effects of
the enclosure itself. A switch is provided on the cross-
over network for the optional selection for use as a fully
passive network or a section of a bi-ampified system.
High F’requencp Compression Driver
Treble reproduction is provided by a wide range com-
pression driver capable of high power output and
linear response characteristics. Its 1 75inch edgewound
aluminum ribbon voice coil is suspended within a
powerful magnetic field produced by a lo-pound
magnetic assembly energized by an Almco V magnet.
The aluminum diaphragm is pneumatically formed
of anodized aluminum foil Output of the diaphragm
is directed through the concentric channels of a phasing
plug prior to final distribution by the horn/lens assembly
Horn/Lens Assembly
Controlled high frequency distribution is accomplished
by an exponential horn and slant-plate acoustic lens
The cast construction of the horn provides rigidity to
eliminate resonance. Its taper rate determines the
vertical dispersion pattern of the assembly and causes
the waveform generated by the compression driver to
expand at a controlled rate, providing the proper
acoustic load on the driver diaphragm. The acoustic
lens is analogous to a divergent optical lens, regulating
the distance traveled by energy at various points along
the wavefront. The precisely calculated hyperbolic
curvature on the projecting surface of the lens determines its specific horizontal distribution pattern
The acoustic lens is mounted with hook-and-pile
mounting tape so it can be remounted allowing the
cabinet to be oriented vertically or horizontally
Ultra-High hequency Dansducer (4333A System Only)
Overtones extending to 20,000 Hz are reproduced by a
compression driver having an integral diffraction horn.
The 1.75mch edgewound aluminum ribbon voice coil
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Low F’requency Loudspeaker
Accurate, solid low frequency reproduction is provided
by a 1 S-inch loudspeaker The cone is selected for
optimum stiffness, density and mass to provide the
critical low frequency bandwidth and transient response
required for monitor applications while maintaining
high efficiency Its 4-inch copper voice coil is manufactured of wire milled to a flat ribbon, then tightly
wound on the narrow edge by hand. Edge winding of
the voice coil increases the amount of conductor in the
magnetic field, resulting in greater transient response
and efficiency Closed construction and precise machining of the 19pound magnetic assembly concentrates all
the magnetic potential of the Alnico V magnet in the
voice coil gap.
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is suspended within an intense magnetic field provided
by a 3%pound magnetic assembly energized by an
Alnico V magnet. The voice coil is bonded to a ring
_,%aphragm pneumatically formed of aluminum alloy
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foil. The diffraction horn maintains a wide, controlled
dispersion pattern, even at extremely high frequencies.
Requency Dividing Network
The 4331A and 4333A systems are provided with a high
level, passive frequency dividing network. The circuitry
has been designed with consideration for the various
performance characteristics of the driver; and their
locations on the enclosure baffle panel. The networks
have been designed for continuous high power application; capacitors are non-inductive, non-polarized types
with high AC current capacity and special inductors
are used to minimize power losses within the network.
Each inductor is calibrated on a sensitive electronic
bridge and its value set precisely
The networks are equipped with terminals and
switch so that they’may be used for high frequency
transitions as bi-amplified systems or full passive metworks for conventional systems.
Enclosure
In keeping with current trends in studio design that
encourage creativity JBL studio monitor enclosures
feature contemporary styling and are offered in two
finishes, each with a complementary grille color The
enclosure, however, contributes as much to performance
:IS it does to the monitor’s handsome appearance. The
b
internal volume of the enclosure and physical configuration of the ducted ports are carefully designed to properly load the new low frequency loudspeaker for
optimum bass response and to control cone excursion,
thus minimizing distortion and maximizing power
handling capacity of the driver. To eliminate resonance,
the enclosure is constructed of dense %- and l-inch
stock with a 15.~1~ baffle panel; all joints are carefully
interlocked and glued; the back, side, top and bottom
panels are lined with acoustic damping material and
are each stiffened by multiple braces glued and
screwed to the panel and to the adjacent surfaces of
the enclosure.
Response
Test Parameters
The accompanying graph and specifications were
compiled from measurements made under standard
laboratory test conditions. The complete loudspeaker
system, including the enclosure, was mounted flush in
the center of a large, flat baffle in an anechoic environment. Calibrated condenser microphones were suspended at a measured distance from the sound source,
sufficiently out of the near field. All associated electronic
equipment was checked and calibrated before tests
were run.
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Maximum Power Input’
(Bi-amplification
configuration)
Below 800 Hz
Above 800 Hz
75 watts continuous sine wave
75 watts continuous sine wave
30 watts continuous sine wave
Nomrnal Impedance 8 ohms
Power output*
4331 A
4333A
100.5 dB SPL
101 dB SPL
Measured at 3.0 m (10 ft) in a room
volume of 57 m3 (2000 cu ft) with
% rated power input
Frequency Response
4331 A
Sine Wave, On-Axis
X-Octave Band
(500 Hz Reference)
35 to 15,000 Hz, 13 dB
-4 df3 at 31.5 Hz,
-1 dB at 1 kHz,
-1~2 dB at 10 kHz
4333A
Sine Wave, On-Axis
%-Octave Band
(500 Hz Reference)
35 to 20,000 Hz &3 dB
-4 dB at 31.5 Hz,
-0.5 dB at 1 kHz,
+2 dB at 20 kHz
Polar Response
4331 A
4333A
No less than -3 dB at 60” horizontal
and 30” vertical to 12 kHr
No less than -3 dB at 60” horizontal
and 30” vertical to 16 kHz
93 dB SPL measured at 1 m (3.3 ft)
wrth l-watt Input averaged from 100
to 1000 Hz
44 dB SPL measured at 9.lm (30 ft)
wdh I-mrlliwatt Input averaged from
100 to 1000 Hz
Distortion
% Power, 99 dB
SPL/3.0 m (loft),
Single Frequency
1% or less thrrd harmonrc generation
from 35 to 800 Hz
2% or less thrrd harmonrc generatron
above 800 Hz
Crossover Frequencies4
4331 A
4333A
Frnrsh
Grille
800 Hz
800 Hz and 8500 Hz
Textured gray or orled walnut
Black fabric wrth the gray frnrsh;
Dark blue fabrrc wdh walnut
Enclosure Volume 156 litres 5.5 cu ft
Enclosure Dimensions 781 mm x 578 mm x 514 mm
Net Weight
4331 A
4333A
Shipping Weight
4331 A
4333A
Accessories
(for bi-amplification)
‘Power amplifier headroom recommendation is 3 dB minimum. i.e., for a E-watt
rating use a IV&watt amplifier.
2Power output measured with a B&K Impulse Precision Sound Level Meter.
3Unlike many “theater type” loudspeaker systems that exhibit sensitivity peaks in the
midrange region. the 433tA and 4333A provide substantially the same sensitivity
through the full range of audible frequencies. Measured sensitivity below 500 Hz or
above X03 Hz may be considerably greater than that of other systems with higher
sensitivity ratings.
4The 52-5123 crosswer card installed in a JBL electronic frequency dividing
network will provide the appropriate crossover characteristics
4333A in bi-amplification configuration. If another electronic network is used.
a lPdB/octave filter slope will provide the closest approximation of the 52-5123.
Caution Sound pressure levels produced by the 4331A or4333A may cause
permanent heanng loss. The suggested max,m”m exposure IS 115 d BA for no more
than 15 m,n”tes. (Department of Labor Bullet,” #334)
JBL continually engages in research related to product improvement. New materials.
production methods and design refinements are introduced into existing products
without notice as a routine expression of that philosophy. For this reason. any current
JBL product may differ in some respect from its published description but will always
equal or exceed the original design specifications unless otherwise stated.
JBL Professional Products are not intended for household use.
30% rn x 22% in x 20% rn
57 kg 125 lb
59 kg 129 lb
60 kg
62 kg 136 lb
132 ib
5233 Electronic Frequency Dividing
Network, single channel: 5234 Electronic Frequency Dividing Network,
dual channel; 52-5123 Crossover Card,
required for the low frequency
transition
for
the
433tA and
.J
\
Professional Division
James B. Lansing Sound, Inc.
8500 Balboa Boulevard
Northridge, California 91329
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