The 5234A Electronic Frequency Dividing Network is designed for use with studio monitor or sound reinforcement loudspeaker systems to provide a cleaner signal from the power source directly to the Individual loudspeakers of the system. By dividing the audio spectrum before power amplrfrcation, treble tones are separated from, and unaffected by, bass frequencies. The result is more efficrent utilization of available amplifier power. Direct coupling to the loudspeakers also eliminates the insertion loss typical of most passive networks and permits realization of the maximum damping factor available from a given amplifier. The 5234A, a dual-channel unit, can be used for biamplification of two loudspeaker systems or to control both transition points in a tnamplifred system. The latter can be accomplished by utilizing one channel for the lower crossover frequency and the other channel for the high frequency transition. The 5234A IS an electronic crossover network utilrzrng active filters It exhibits unity gain in the pass band, provides adequate output to drive any quality amplifier, and operates at extremely low distortion levels at full rated output. A programmable high pass filter removes subsonic energy below the lowest usable speaker frequency.
The crossover frequency is determined by inserting the proper printed circuit card into each channel circuitry. Cards with fils ter slopes of 18 dB per octave are available for crossover frequencies of 80H.z 500 Hz, and 800 Hz. Cards with filter slopes of 12 dB per octave are available for the following frequencies; 250 Hz, 500 Hz, 800 Hz, 1200 Hz, 5 kHz, and 7 kHz. In addition, cards are available with specific crossover characteristics for the JBL 4343,4350,4345,4355,4430 and 4435 studio monitors Blank cards are also available to allow construction of circuitry for other crossover frequencies. The units are shipped with two cards that convert each channel to a unity gain audio distribution amplifier having two identical outputs. Each channel of the 5234A is provided with a continuous level control for high frequency shelving.
Model 5234A Electronic Frequency Dividing Network
Architectural Specifications

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The sound system described herein shall be equipped with separate power amplifiers for low (midrange) and high frequency program material. A dual-channel low-level active network shall be provided to filter program material at the designated crossover point(s).The inputs shall be transformerless, symmetrical and floating. Dual-in-line switching shall provide selectable low frequency equalization and subsonic filtering.The frequency dividing network shall be equipped with separate output buffer amplifiers for low and high frequency program material. Crossover frequency selection shall be accomplished by internally mounted plug-in circuit modules. Each module shall be designed with the crossover frequency printed in such a position as to be easily read through a window In the front panel of the electronic frequency dividing network. The designated crossover frequency shall be the point at which the slopes of the pass band curves cross and where each is 3 dB down from the average output level.This point.shall be within -+ 10% of the designated frequency. The filter slope shall be 12 dB or 18 dB per octave. The unmodified frequency response of the dlvidlng network shall

I .Specificatiotls

Gain Rated Output Distortion
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Frequency Response Crossover Frequency Filter Slope High Pass Filtering Filter Frequency 20 Hz 20 Hz 30 Hz 30 Hz 30 Hz 40 Hz 40 Hz Input Impedance toad impedance Output Impedance Channel Isolation Signal/Noise Ratio Controls

0 cfB in,fhe pass bancf 6.2 V [+ 18 dBv) 0.01% THD, 20 Hz-20 kf-tt @ + 18 dBv into > 100 kn load -c0.5 dB, 20 Hz-20 kHz Selectable by plug-in module, - 3 dB crossover point f 10% 12 dB/octave or 18 dB/octave Level at Filter Frequency -3dB +6dB -5.5 dB - 1.5 dB +6dB -3 dB +6dB 50 kn, symmetrical floating 600 R or greater 50 a, unbalanced >70 dB, 20 Hz-20 kHz ~90 dB, 20 kHz equivalent bandwidth2 High frequency level Power Supply voltage select
Filter Q 0.707 ;.54 0.0.707 2
be 20 Hz-20 kHz, to.5 dB. DistortIon shall be less than 0.03% THD at + 18 dB, and 0.01% THD, + 18 dBv into a 100 kn load. Signal-tonoise ratio shall be greater than 90 dB at rated output, 20 Hz-20 kHz eaulvalent bandwldth. Internal provisIon shall be made for switch selectlon of parallel monaural low frequency outputs A high pass filter with 12 dB per octave slope shall remove subsonlc energy below the lowest usable speaker frequency A dual In-line switch shall provide the following programmable options for the subsonlc filter a Flat frequency response slope, Q = (Butterworth) slope, Q = 2 (6 dB boost @ 20 kHz) slope, Q = slope, Q = 0 84

Connections

Screw-type terminal strip 6.3 mm (X in) phone jacks, three-circuit (tip-ring-sleeve) symmetrical, floating Screw-type terminal strip Output 6.3 mm phone jacks, two-circuit, unbalanced 6 W, 100-120/200-240 V AC, Power Retlukemerits 50/60 Hz 5oC (41oF) to 55oC (132oF) I:. Operating Temperafure 483mmx44mmx194mmdeep Dimensions 19inxlX inx75/8 indeep 1.8 kg 4 lb Net Weight Shipping Weight 6~ lb 3 kg Crossover Cards Cone required per channel? 51-513CLblank 18 dB/octave 51-5132-500 Hz 51-5133-800 Hz 51-5138-80Hz 51-5145-For 4345,4355 studio monitors 52-5120-blank 12 dB/actave 52-5121-250 Hz 52-5122-500 Hz 52-5123-800 Hz 52-5124- 1200 Ht 52-5125-5000 Hz 52-5127-7000 Hz 52-5130-For 4430,443s studio monitors 52-5140-For 4343,435O studio monitors Input
~OdBv=0775Vrms(tmWinto6M)O), p&q&es 20 Hz-20
b 20 Hz hlg h pass filter, 12 dB/octave c 20 Hz high pass filter, 12 dB/octave d 30 Hz high pass filter, 12 dB/octave e 30 Hz high pass filter, 12 dB/octave
f 30 Hz high pass filter, 12 dB/octave slope, Q= 2 (6 dB boost
@30 Hz) g 40 Hz hlg h pass filter 12 dB/octave slope, Q = (Butterworth) h 40 Hz high pass filter, 12 dB/octave slope, Q= 2 (6 dB boost @40 Hz)
Isolation between channels shall be greater than 70 dB. The electronic crossover network shall be a JBL 5234A

output

terminals
for the 5234A loudspeaker

channels

can be utlllzed the low channel
for trlampllflcatlon frequency This allows and high

of a single

system

by connecting

of one channel completely

to the Input Independent

termmals adjustment

of the other

separate,

of the mldrange

frequencies

kbiz equivalent

band&&h

filter.

Professional

Division

JBL/harman international

Callfornla 91329 U S A

SS-5234A Printed in U.S.A
JBL Incorporated 8500 Balboa Boulevard, P 0 Box 2200, Northndge,

The 4355 Studio Monitor

The JBL 4355 is the latest result of an engineering undertaken loudspeaker to create, regardless for monitoring recording study studio High Frequency Compression Driver d

of cost, the optimum

sessions and for final
Reproductron from kHz to IO kHz is accomplrshed by a massrve compression driver energized by a magnetic assembly weighing wound featuring kg (24% lb) The 100 mm (4 In) edgeribbon voice coil, suspended an aluminum diamond In a magnetrc diaphragm that aluminum
mixdown of master tapes. A four-way system designed for biamplification, it achieves inherently smooth reproduction from 28 Hz to 20 kHz, controlled high frequency dispersion, and exceptional transient performance. In addition, the 4355 is capable of wide dynamic range with low distortion and of the high acoustic output required for precise reproduction of the original mastering sounds. It is an indispensable and mixdown, and reproducing tool, not only for analysis of complex. but also for subjective
field of T (18,000 gauss),drives a three-dimensional

pattern surround

provides improved high frequency response and increased relrabrlrty Proper phasing of the wavefront IS assured by use of a phasing plug of die-cast concentnc of an extremely exponential horns The combination diaphragm powerful, transient efficient magnetic response and
the entire studio recording
assembly, edge-wound dynamrc range.
vorce coil, and large yet lightweight

results in exceptional

Biamplification The two low frequency -of the other components significant performance tortion, particularly likely to overload loudspeakers advantages are driven independently offers disin the system. Biamplification in terms of reducing
Horn/Lens exponential quency
Assembly driver is distributed by an lens. horn combined wjth a slant-plate lens without acoustic
The output of the compression The rigid horn casting couples driver to the acoustic or distortion. resonance
at high volume a single amplifier.
levels that would be more
the output of the high freadding audible to a divergent of high

Low Frequency

Loudspeakers loudspeakers mounted
The 11 plates of the lens, set at an analogous propagation controlled
Two 380 mm (15 in) low frequency
angle of 38: operate optical lens, provrdrng frequency energy

in a manner

in a ported enclosure provideaccurate reproduction and high power handling at very low frequencies. The use of two drivers allows twice the power input to the low frequency section, resulting in a 3 dB increase in acoustic output. Each loudspeaker fabricated is driven by a 100 mm (4 in) diameter of edge-wound copper voice coil in a ribbon wire, operating

Ultra-High

Frequency Transducer 4
The highest octave of the audio spectrum IS reproduced by a compression driver specifically designed for ultra-high frequency magnetic reproduction assembly and dispersion Its 2 kg (4% lb) aluminum pneufoil stock. 90 slot develops a flux density of T (16,500
magnetic field with a flux density of 1.2 T (12,000 gauss). The 8.5 kg (18% lb) magnetic assembly incorporates JBL s unique Symmetrical Field Geometry reduces second harmonic distortion (SFG) design that to inconsequential
gauss) and drives a 44 mm (1% in) edge-wound ribbon voice coil.The matically Output
driver uses a ring diaphragm a diffraction
levels. Careful choice of suspension elements, taking into account their interaction with the voice coil motion, results in a driver with tight, controlled transient response and complete freedom from dynamic instabilities. A compliant cone termination allows long excursions traveling and damps spurious reflections within the cone material.

formed directed

of mm (0.002 in) aluminum through
horn providing to the diffractron

drspersion

in the plane perpendicular

while restricting dispersion in the vertical plane to approxrmately 4OP The device maintains response wrthrn a tolerance of *3 dB to 20 kHz.

Midrange

Loudspeaker lying in the region between 290 Hz and by a 300 mm (12 in) loudspeaker

Frequency

Dividing Network loudspeakers operate to 290 Hz and

Music fundamentals

The low frequency

1.2 kHz are reproduced

require an attenuation
rate of 12 dB per octave below and
housed in a sealed subchamber and driven by a 100 mm (4 in) edge-wound copper ribbon voice coil. The SFG design of the magnetic structure results in exceptionally low levels of second harmonic distortion. The magnetic assembly weighs 9.5 kg (21 lb) and produces a flux density of 1.2 T (12,000 gauss) in the voice coil gap. The driver achieves high acoustic efficiency and effortless extreme volume levels. reproduction, even at
above the crossover frequency Transition may be accomplished with a JBL 5234A dual channel Electronic Frequency Drvrdrng Network designed or with one of several electronic available for the 4355 IS available crossovers card or filtering devices commercially specifically JBL 5234A A crossover

for use in the

The midrange, L

high frequency,

and ultra-high

frequency net-

Test Parameters The accompanying graphs and specrfrcatlons were comprled from measurements made under standard laboratory test condrtrons. The loudspeaker calibrated measured system was mounted flush in the A center of a large, flat baffle In an anechorc environment

drivers are regulated

by a high-level

passive crossover

work of the L-C type specifically designed and tested for operation with the transducers of the system. Transition between the midrange loudspeaker and the high frequency compression driver occurs at 1.2 kHz at the rate of 12 dB per octave. At 10 kHz, the ultra-high frequency driver is brought into operation at 18 dB per octave. Level controls are provided.
condenser microphone was suspended at a distance from the sound source, sufficiently out was
of the near field All associated electronic equipment checked and calibrated before tests were run.
Enclosure The enclosure of the 4355 incorporates two acoustic cham-
bers. The two low frequency loudspeakers are housed in a bass reflex chamber which has an internal volume of 265 liters 19.5 ft3). Proper Ydistributed midrange loudspeaker loading to 32 Hz is accomplished by a port consisting of two large curved tubes. The in a second, sealed sub-

is mounted

chamber, 48 liters (1.7 ft3) in volume and designed to prevent acoustical interaction with the low frequencydrivers.Thesubchamber also attenuates output of the midrange unit below 200 Hz, thus reducing unwanted peaks in total system response. The enclosure is constructed of 25 mm (1 in) stock for maximum rigidity with minimum weight. Joints are carefully fitted and heat treated; the enclosure is architecturally braced to prevent unwanted resonances, and the interior surfaces are padded to damp spurious reflections and standing waves within the acoustical chambers. One-third octave band response of the 4355, taken on-axis with pink noise. Measured response contour of a typical 4355 does not differ by more than 2 dB from the above curve.

JBL continually engages in research related to product nprovement New materials. product tlon methods and design refinements are introduced mlo existing products whout noWe as a routine expression of that philosophy For this reason. any current JBL product may differ m some respect from its publ!shed descrlptlon but will always equal or exceed the orlgmal speciflcatlons unless otherwse stated

%k/harman InternatIonal

James B. Lansing Sound,
Inc. 8500 Balboa Boulevard,

P.0. Box 2200,

No&ridge,

California

91329 U.S.A.
61183 554355,9-81 inusP Printed