A
Safety Procedure for
Initial
Powering
Up of The System
Prior to
full
operation of the
dividing
network/
amplifier/loudspeaker system, it is
important
to
verify
that
the various frequency bands are con-
nected to the correct amplifiers and loudspeakers.
The
following
procedure should be
followed
for
each program channel
prior
to operation.
1.
With
all
POWER
off (amplifiers included), set
the 5234A HIGH
FREQUENCY
LEVEL
control
at
#2,
and adjust the program source
output
to
minimum level. (The source may be wideband pink
noise or music.)
2.
If the power amplifiers are equipped
with
level
controls, adjust them to approximately one quarter
of the maximum.
3.
Turn on the program source, the 5234A, and
the power amplifier(s) for the channel under test.
4.
Gradually increase the program source level
until
it just becomes audible.
CAUTION:
If the sound comes mainly
from
the midrange
or high frequency driver(s), shut off all power immediately
and check all wiring. Since the HIGH
FREQUENCY
LEVEL
control is turned down, the low frequency transducer
should
become audible first; if this is not the
case,
and low
frequency sounds are emerging
from
higher frequency
drivers,
the output wiring is reversed somewhere between
the 5234A and the loudspeaker system. Continued opera-
tion
could easily damage compression drivers.
5.
With
the low frequency transducers producing
bass,
gradually increase the 5234A HIGH
FRE-
QUENCY
LEVEL
control. (In a
triamplified
system,
do this first on the channel which feeds the
high
frequency driver, Channel 1.),Correct system wiring
will
be verified if the treble component of the pro-
gram material increases in level and is emerging
from
the
high
frequency driver. (In a
triamplified
system,
repeat this procedure for the channel feeding the
midrange driver, and verify the HF
LEVEL
control
increases
midrange
output.)
Level
Control Adjustment
There
are several points in the sound system
where levels can be set. Naturally, it is
important
that
the gain structure be established correctly
so
that
no
input
is overdriven, and so
that
the best
signal-to-noise
ratio
possible is maintained. Beyond
that,
however, it becomes necessary to
obtain
the
correct level balance between the various frequency
bands so
that
overall frequency response conforms
to the desired characteristic.
In many instances, manufacturers of multi-
amplified loudspeaker systems provide instructions
for balancing levels of the individual drivers in the
system.
In the absence of formal instructions, or in
the
case
of custom loudspeaker systems, balance
can
be established by adjusting levels to achieve the
flattest response as measured
with
a real-time
analyzer
and a pink noise source (much like the
technique described in the System Phasing and
Signal
Polarity Section of this manual). Alternately,
subjective evaluation of familiar program material
can
provide a
good
means to balance levels. In
fact, perfectly
flat
electro-acoustic response is
seldom desirable for the listener, so subjective
evaluation may be the preferable technique.
NO TE:
Each
program channel should be adjusted
indi-
vidually. Subjective evaluation should be made while
seated
in the normal listening location. If subjective analysis
is
to be
used
and the power amplifiers are equipped
with
level
controls,
initially
adjust those controls to one half
their rotation and then regulate as
necessary.
Subjective
Adjustment of Biamplified Systems
NOTE:
The following procedure applies to
each
channel
of a 5234A
used
in a dual channel biamplified
system.
1.
With
the HIGH
FREQUENCY
LEVEL
control
at #0, adjust the program source
output
for a
comfortable listening level.
2.
Rotate the HIGH
FREQUENCY
LEVEL
con-
trol
clockwise
until
a satisfactory
high
frequency
balance
has been obtained in the program material.
If necessary,
trim
the source and/or amplifier levels.
3.
Turn off the first channel's signal source and/or
amplifiers, and adjust the other channel per steps 1
and 2 above.
NOTE:
Once the HIGH
FREQUENCY
LEVEL
and
amplifier level controls have
been
adjusted in this manner,
readjustment is not generally needed.
Some
method of
locking the power amplifier level controls (or at least
marking the desired settings) is recommended.
Subjective
Adjustment of Triamplified Systems
NOTE:
When both channels of the 5234A are
used
for a
triamplified loudspeaker
system,
the recommended
installation is
such
that
the CHANNEL 1 HIGH
FRE-
QUENCY
LEVEL
CONTROL
regulates the output of
the midrange driver, and the CHANNEL 2 HIGH
FRE-
QUENCY
LEVEL
CONTROL
governs the high frequency
driver
(Refer
to the General Applications
Section
and
Figure
19).
1.
With
both
HIGH
FREQUENCY
LEVEL
controls at #0, adjust the program source
output
for a comfortable listening level.
2.
Rotate the CHANNEL 1 HIGH
FREQUENCY
LEVEL
control
clockwise
until
a satisfactory mid-
range level has been obtained.
3.
Rotate the CHANNEL 2 HIGH
FREQUENCY
LEVEL
control
clockwise
until
a satisfactory
high
frequency balance has been obtained. If necessary,
trim
the source and/or amplifier levels.
4.
It may be necessary to readjust the midrange,
source
and amplifier levels to achieve the most
desirable overall balance of the loudspeaker system.
5.
In a two-channel system,
turn
off the first
channel's
signal source and/or amplifiers, and adjust
the other channel per steps 1
through
4 above.
NOTE:
After the HIGH
FREQUENCY
LEVEL
controls and
amplifier level controls have
been
adjusted in this manner,
readjustment is not generally needed.
Some
method of
locking the power amplifier level controls (or at least
marking the desired settings) is recommended.
System
Phasing & Signal Polarity
A
major factor in the natural sound character of
a
multi-way loudspeaker system is the relative
polarity
and phase relationship between the various
14
To Next Page
Loading...
