Subjective Method—
If test instrumentation is not available,
proper results can be obtained as follows:
1. Adjust volume level for comfortable listening and set
approximate system balance using pink noise or the noise
heard between stations of an FM tuner.
2. Listen to a recording of a male voice long enough to
become accustomed to the performance of the loud-
speaker system.
3. Reverse polarity of the high frequency loudspeaker, which
will produce a change in voice character. When the trans-
ducers are properly phased, a recorded male voice should
sound natural and exhibit presence [or an "up front"
quality], in contrast to the undesirable "hollow" sound
heard when transducers are out of phase.
Note: If the crossover frequency lies above 2 kHz, reversing
polarity of the high frequency c o m p o n e n t will create little
(if any) perceptible difference in system performance. The
"correct" polarity in such a case will be that which yields
the most natural quality with a variety of program material.
Once proper phase among the transducers of a loud-
speaker system has been determined, other loudspeaker
systems in the installation (assuming they are the same
model] may be phased accordingly. If different loudspeaker
systems are used, establish c o m m o n phase among the low
frequency drivers and follow the above procedures for
each system.
Lovol Control Adjustment
In most instances, manufacturers of multi-amplified
loudspeaker systems provide instructionsfor balancing levels
of the individual drivers of 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 on a real time analyzer, as
described above, or on the basis of subjective evaluation of
familiar program material (or, more accurately, by using pink
noise or the noise between FM stations] as described in the
following paragraphs.
Each program channel should be adjusted individually;
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 the controls to one half of their full rotation
and then regulate as necessary.
Subjective Adjustment of Bi-Amplified Systems—
The
following applies to a 5233 or to each channel of a 5234 used
in dual channel bi-amplification.
(
2. Rotate the network control clockwise until a satisfactory
high frequency balance has been obtained in the program
material. If necessary, trim source or amplifier levels.
Subjective Adjustment of Tri-Amplified Systems-
When
both channels of a 5234 are used for a tri-amplified loud-
speaker system, it is generally installed so that the Channel 1
level control regulates the output of the midrange driver
and the Channel 2 level control governs only the high
frequency driver.
1. With both High Frequency Level controls at "0',' adjust the
source level for comfortable listening.
2. Rotate the Channel 1 level control clockwise until a
satisfactory midrange level has been obtained in the pro-
gram material. If necessary, adjust source or amplifier levels
as appropriate.
3. Increase the Channel 2 level until a satisfactory high
frequency balance has been obtained. It may be necessary
to readjust midrange, source, or amplifier levels to achieve
the most desirable overall balance of the loudspeaker
system. Once high frequency and amplifier output levels
have been established, readjustment is not generally
needed. Some method of marking or locking the power
amplifier level controls is recommended.
1. With the High Frequency Level control a t " 0 " adjust program
source level for comfortable listening.
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