JBL 4343 Oak Cabinets/ blue baffles Collectors item
These are 30 years old and in fabulous shape. The 10" mid woofers just got new
surrounds installed and the 15" woofers received new surrounds about 5 years
ago.
These are true studio monitors, no telling how many albums from the 70’s were
mastered with speakers just like these.
These speakers sound fabulous, very explosive and realistic sound. They are 93
dB at 1 watt, I am using a clone of the old Dynaco sc 35 17.5 watt per channel
EL84 power amp and I can’t turn it up all the way it gets too loud.
They image great and the speakers disappear if you get them far enough apart. I
have them nearly in the corners of my listening room. Voice is very natural and
realistic on these and classical music sounds very realistic like you are there
on the 4343.
They are a 4 way with a super tweeter, midrange/tweeter horn, a 10" mid bass
woofer and 15" deep bass woofer.
These are beautiful and the sound is amazing.
The Main biniding posts are the old fashioned JBL type that are spring loaded
and you push them in to insert naked wire, the lower ones which are for single
amping are loose and the speaker would benefit from having them replaced with
modern 5 way binding posts.
JBL 4343
The 4343 represents an extension of the research and development effort that
produced the 4350 Studio Monitor JBL’s top system, which uses dual low frequency
drivers. This new monitor accurately reproduces the full range of fundamentals
and overtones in music at sound pressure levels approximating those of an
original performance. The exceptionally smooth wide-band reproduction clarity,
transient response and low distortion of the 4343 results from total integration
of the components that make up the four-way system so that each transducer
reproduces only that portion of the audio spectrum for which it is specifically
designed Deliberately restricting the operating bandwidth of the individual
drivers results in maximization of each unit’s transient response. Another
benefit of bandwidth limitation is that each driver operates only in the region
of the audio spectrum through which it exhibits controlled sound distribution,
thus a dispersion pattern for the complete system is achieved which is ideal for
studio use. The passive frequency dividing network supplied with the 4343
controls the acoustic output of all the individual transducers, and may be
switched for bi-amplification.
Features Accurate smooth reproduction from 35 to 20,000 Hz, ±3dB 44 dB SPL at
30 feet with a 1-milliwat input 101 dB SPL at 10 feet at one-half rated power
input Mountable in vertical or horizontal orientation Components: 15" low
frequency loudspeaker, 10" midrange loudspeaker, High frequency compression
driver with horn/lens assembly and ultra-high frequency transducer Balance
conrols located behind the removable grille Rear mounted switch for
bi-amplification or full passive crossover Oiled walnut or textured gray
enclosure
Ultra-High Frequency Transducer Overtones above 9000 Hz are reproduced by a
compression driver and diffraction horn specifically designed for reproduction
and dispersion of energy at the extreme high end of the audio spectrum. The
compression driver consist of a 3-1/4 pound magnetic assembly energized by an
Alnico V magnet. The 1,75 inch edgewound aluminum ribbon voice coil,
suspended within a field having a flux density of 16,500 gauss is affixed to a
heat resistant support bonded to a ring diaphragm pneumatically formed of .0022
inch thick aluminum foil. Output from the diaphragm is directed through the
integral diffraction horn, which produces the unit’s wide high frequency
dispersion pattern.
High Frequency Compression Driver The high frequency compression driver
provides smooth, accurate response and is capable of delivering the high power
output levels required in monitor applications. The closed magnetic assembly is
energized by an Alnico V magnet, weighs 10 pounds and achieves a flux
density of 19,000 gauss in the voice coil gap. A ring of pure silver deposited
on the circumference of the pole piece maintains uniform impedance through the
highest frequencies, extending the bandwidth of the driver. The diaphragm,
pneumatically formed of .002-inch thick aluminum foil stock is driven by a
1,75-inch edgewound aluminum ribbon voice coil. The wavefront emerging from the
diaphragm is directed through the concentric channels of a phasing plug prior to
distribution by the horn/lens assembly.
Horn/Lens Assembly Output from the high frequency compression driver is
distributed through a controlled pattern by the horn/lens assembly. The horn is
formed of a rigid casting to eliminate spurious resonance. The exponential taper
rate of the horn controls the expansion of the wavefront providing proper
acoustic loading of the driver diaphragm and determines the vertical dispersion
pattern of the assembly. The acoustic lens functions in a manner analogous to a
divergent optical lens. Its 11 plates set at a precise angle to the enclosure
baffle panel, provide controlled propagation of high frequency acoustic energy
in the horizontal plane.
Midrange Loudspeaker The smooth performance and instantaneous transient
response of the 10-inch midrange loudspeaker is largely responsible for the
outstanding instrumental clarity, vocal definition and dimensional accuracy of
the system. Its closed magnetic assembly weighing 6-1/2 pounds, concentrates all
the energy of an Alnico V magnet in the voice coil gap. The 3-inch edgewound
copper ribbon voice coil is suspended within a powerful magnetic field having a
flux density of 10,000 gauss. The integrally stiffened cone is terminated with
an wxclusive JBL ring compliance that allows long excursion while maintaining
linear travel.
Low Frequency Loudspeaker The 15-inch low frequency loudspeaker is mounted in a
ported enclosure having an internal volume of 5,5 cubic feet. The driver
features extreme, solid low frequency reproduction with smooth response well
past its crossover frequency. The unit is energized by a 13-pound magnetic
assembly concentrates a magnetic field having a flux density of 12,000 gauss in
the voice coil is hand wound on a heat resistant support. The support is affixed
to a rigid cone having optimum mass density and rigidity for exceptional
transient response and maximum efficiency with the bandwidth of the driver.
Frequency Dividing Network The 4343 is provided with a high level, passive
frequency dividing network for the three transitions of the system. The network
is fitted with a rear-mounted switch and separate input terminals for
bi-amplification. The circuitry has been designed with consideration for the
various performance characteristics of the drivers and their location on the
enclosure baffle panel. The network has 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. A special circuit card providing the precise
crossover characteristics for bi-amplification of the 4343 is available for use
in the JBL 5233 or 5234 Electronic Frequency Dividing Network. Conventional
electronic networks can be used, but they may not have the exact frequency and
filter slope characteristics required for optimum performance of the system.
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 much more than striking appearance. The low frequency
loudspeaker is housed in a chamber having an internal volume of 5,5 cubic feet.
The midrange loudspeaker is enclosed in a separate, isolated sub-chamber having
an internal volume of 0,5 cubic feet. The internal volume of the acoustic
chambers and physical configuration of the ducted ports are carefully calibrated
to properly load the low frequency and midrange loudspeakers for optimum bass
response and to control cone excursion, thus minimizing distortion and
maximaizing power handling capacity of the drivers. To eliminate resonance, the
enclosure is constructed of dense 3/4-inch and 1-inch stock with a 15-ply 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. The baffle section which supports the midrange, high frequency
and ultra-high frequency trasducers may be rotated 90° left or right for
horizontal system instalations.
Specifications Maximum Power Input Bi-amplification: Below 300 Hz : 75 watts
continuous sine wave Above 300 Hz : 75 watts continuous sine wave Simgle
Amplification: 75 watts continuous sine wave Power Output: 101 dB
SPL Measured at 3,0 m (10 ft) in a room volume of 57 m³ (2000 cu ft) with half
rated power input Nominal Impedance: 8 ohms Frequency Response: 35
to 20,000 Hz, ±3 dB Sensitivity: 93 dB SPL measured at 1m (3,3 ft) with
1-watt input averaged from 100 to 1000 Hz; 44 dB SPl measured at 9,1m (30 ft)
with 1-milliwatt input averaged from 100 to 1000 Hz Polar Response: No
less than -3 dB at 60° horizontal and 30° vertical to 16 kHz Distortion: 1/2
Power, 99 dB SPL/3,0m : 1% or less third harmonic generation from 35 to 800 hz
Single Frequency : 2% or less third harmonic generation above 800 Hz Crossover
Frequencies: 300, 1250 and 9500 Hz Finish: Textured gray or oiled walnud
Grille: Black fabric with the gray finish; Dark blue fabric with walnut
Enclosure Volume Low Frequency Chamber : 156 litres (5,5 cu ft) Midrange Chamber
: 14 litres (0,5 cu ft) Enclosure Dimension: 1050 x 635 x 435 mm (41-3/8 x
25 x 17-1/2 inch) Net Weight: 79 kg (175 lb) Accessories for
bi-amplification: 5233 Electronic Frequency Dividing Network, single
channel; 5234 Electronic Frequency Dividing Network, dual channel; 52-5140
Crossover Card, required for the low frequency transition of the 4343.
Each speaker weighs in at about 160 lbs.