Single Channel Tri-ampllficatlon
5232 ELECTRONIC FREQUENCY DIVIDING NETWORK
PROGRAM
SOURCE
Shielded cable
is
necessary
for all
input
and
output connections,
as
shown.
Make certain that
the
shield
is
properly connected
to the
ground terminal.
AMPLIFIER
AMPLIFIER
AMPLIFIER
LOUDSPEAKER SYSTEM
Operation
Verification
Of
System Wiring
It
is
imperative that each output
of the
electronic frequency
dividing network
be
properly connected. Inadvertent
exchange
of low and
high frequency output connections—
at
the
network, power amplifiers
or
transducers—may
result
in
severe damage
to
midrange
or
high frequency
loudspeaker system components.
The following procedure should
be
followed
for
each
program channel prior
to
operation.
1.
With
ail
power off,
set the
High Frequency Level control
at
"2"
and
adjust
the
program source level
to
minimum.
(The
source material
may be
wide-band noise
or
music.)
If the
power amplifiers
are
equipped with level controls, adjust
them
to
approximately one-quarter power.
2.
Turn
on the
program source, network
and
amplifiers
for the
channel under test.
3. Gradually increase
the
program source volume level until
audible.
If
the
sound comes predominately from
the
midrange
or
high frequency drivers, immediately shut power
off and
check
all
wiring.
4. If the low
frequency loudspeaker produces bass, gradually
advance
the
High Frequency Level control.
Correct system wiring will
be
verified
if the
treble com-
^ ponent
of the
program material simultaneously increases
in
level while coming from
the
midrange
and
high frequency
drivers.
Transducer Phasing
One important factor contributing
to the
natural sound
character
of a
loudspeaker system
is the
phase relationship
of
the transducers
for an
octave below
and
above each cross-
over frequency.
Two
suitable methods
for
establishing proper
phase
of the
components
in a
two-way loudspeaker system
are described
in the
following paragraphs. Either
one may be
used,
depending
on the
availability
of
test equipment.
A
three-
or four-way system should
be
treated
in a
similar manner
by
first establishing
the
proper phase
for the
transducers
of the
low frequency transition
and
then progressing
to the
mid-
.
range, high frequency
or
ultra-high frequency transducers,
as applicable.
Objective Method—A real time third octave analyzer,
con-
denser microphone
and a
pink noise source
can be
used
to
establish proper phase
of the
loudspeaker system com-
ponents
as
follows:
1.
Using pink noise
as
program material, adjust system
volume
for
comfortable listening
and set the
levels
of the
individual transducers
to
display flattest overall frequency
response
on the
real time analyzer.
2.
Reverse polarity
of the
high frequency driver and observe
the effect
on
frequency response through
the
crossover
region.
Proper phasing
of the
transducers will have been achieved
when
the
flattest frequency response
has
been obtained
through
the
crossover region,
as
shown
on the
real time
analyzer.
5
5232
HIGH
MID
LOW
Figure
3. The
Wiring
Diagram
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