T h e J B L 5 2 3 1 a n d S232
E l e c t r o n i c F r e q u e n c y D i v i d i n g N e t w o r k s
The 5231 and 5232 are designed for use with studio monitor
or sound reinforcement loudspeaker systems where b i -
amplification or tri-amplification is desirable. The 5231 (single
channel) and 5232 (dual channel) feature unbalanced,
high impedance inputs, unity gain in the pass band and
unbalanced low impedance outputs. The 5231 will provide a
single channel crossover. The 5232 provides two separate
channels with independent crossover action (as in a stereo
installation).
The power switch and pilot light for the unit and a high
frequency level control for each channel are on the front panel
for easy access. The crossover frequency at which each
channel is operating is indicated through a front panel
window. Either model can be mounted in one EIA standard
rack space.
The desired crossover frequency is obtained by inserting
the corresponding printed circuit card into each channel's
circuitry. Crossover cards are available for the commonly
used frequencies of 500 Hz and 800 Hz. Filter slopes are
12 dB per octave with high and low frequency output attenu-
ated 3 dB at the crossover point. Cards are also available with
the specific crossover characteristics required for the JBL
4330,4332,4340 or 4350 bi-amplified studio monitors. In
addition, blank cards can be obtained for construction of
crossover networks for other frequencies (details provided in
the appendix).
Advantages
1.
Lower Distortion—The
use of electronic frequency dividing
networks and multiple amplifiers permits delivery of optimum
power over the desired audio spectrum with minimum distor-
tion. By dividing the audio spectrum prior to amplification, the
individual low frequency and high frequency amplifiers can
perform their functions with greater effectiveness.
2.
Flexibility—\n
sound reinforcement applications it is often
desirable to combine one low frequency driver with several
high frequency units to obtain a controlled dispersion pattern;
thus, one may select amplifiers of the appropriate power for
each group of transducers.
3.
Cost Savings—
When several loudspeaker systems are to
be connected to a single channel, significant cost savings can
be realized since only one electronic frequency dividing net-
work need be used, thereby eliminating the high level passive
crossover networks normally required for each of the loud-
speaker systems. Moreover, since no power is dissipated in
resistive attenuators, the amplifier requirements for high
power sound systems may be substantially less than when
high level dividing networks are used.
I n s t a l l a t i o n
The electronic frequency dividing network receives the pro-
gram signal from a line level s o u r c e — a n audio preamplifier,
studio mixdown console or portable m i x e r — a n d separates the
signal into high and low frequency bands. Outputs from the
network feed the appropriate power amplifiers. Each amplifier,
in turn, drives its respective loudspeaker system components.
Typical installations are diagrammed in Figure
1 .
1
