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PHASING
To test two microphones andlor their cables for proper
phasing, connect them to an amplifier and talk or sing into
them while holding them three or four inches apart. The
sound from the speakers should be the same when talking
into either microphone or directly between them if they
are in phase with each other. If the sound drops drastically,
or if a dead spot is found when talking between the two
microphones, one of them or its cable (low impedance
only) is out of phase. All cables and microphones should
be tested in this manner to insure that they are in phase
with each other.
To change the phase of a low-impedance microphone
cable, either use a Shure AISPR Phase Reverser or inter-
change the wires connected to pins 2 and 3 of the connec-
tor. T o change the phase of a microphone, the microphone
cartridge leads must be interchanged (see Figure 2). This
should be performed by your dealer, the Shure Factory
Service Department, or other qualified service personnel.
IMPEDANCE
Your microphone is wired for low impedance for connec-
tion to low-impedance microphone inputs (rated at 19 to
300 ohms). Low impedance is recommended where long
cable lengths are required or under conditions of severe
hum disturbance. The permissible cable length is practical-
ly unlimited since neither response nor level is appreciably
affected by long cables. Shure Model A95 Series Line
Matching Transformers are available for use in those cases
where a low-impedance microphone line is desirable but
the associated amplifier or mixer has a high-impedance
input. These transformers provide a proper impedance
match between a 19 to 300 ohm microphone line and a
high-impedance input, and are available with various in-
put and output connectors.
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