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UNIDYNE III MODEL 545SD
User Guide
SET SCREW
PLUG ELEMENT
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PIN 3
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GENERALIMPEDANCE SELECTION-
RECEPTACLE END OF MICROPHONE
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The UNlDYNE III Model 545SD is a dual-impedance, unidirectional, FIGURE 1
dynamic microphone. Shipped connected for low-impedance opera-
POLARITY
tion, it features a silent magnetic reed on/off switch.
All cables and microphones should be tested to ensure that they
The UNlDYNE III is a favorite for instrument pickup and recording,
have the same polarity. To test two microphones and/or their
and can be used on lecterns for public address systems such as
cables for proper polarity, connect them to an amplifier and talk or
those used in political conventions and legislatures, convention
sing into them while holding them three or four inches apart. The
halls, hotels, public auditoriums, stadiums, schools, and churches.
sound from the speakers should be the same when talking into
FEATURESeither microphone or directly between them. If the sound drops
drastically, or if a dead spot is found when talking between the two
? Exceptionally uniform cardioid pattern minimizes feedback in
microphones, either the microphones or their cables have opposite
PA applications
polarity.
? Selectable dual-impedance operation
To change the polarity of a microphone cable, either use a Shure
? Silent magnetic reed on/off switch with lock optionA15PRS phase reverser or interchange the wires connected to
? Cardioid dynamicpins 2 and 3 of the three-pin connector at one end of the cable. To
change the polarity of a microphone, the microphone cartridge
? Frequency response: 50 to 15,000 Hz
leads must be interchanged. This should be performed by your
CONNECTIONSdealer, the Shure Factory Service Department, or other qualified
service personnel.
when using the microphone with a balanced input, pins 2 and 3 are
the audio signal carriers. When using the microphone with anSPECIFICATIONS
unbalanced input, use a cable wired with pin 2 as the signal carrierType
and pin 3 connected to the cable shield (ground), such as the
Dynamic
Shure C20HZ high-impedance cable.
Frequency Response
IMPEDANCE SELECTION
50 to 15,000 Hz (see Figure 2)
The microphone is shipped connected for low impedance
Polar Pattern
operation. To change to high impedance, proceed as follows (refer
to Figure 1):Cardioid (unidirectional)-uniform with frequency, symmetrical
about axis (see Figure 3)
1. Remove plug element at receptacle end of microphone by
lmpedance
turning slotted setscrew in (counterclockwise) and carefully
withdrawing plug element from case.Dual. Microphone rating impedance is 150 ohms (250 ohms ac-
tual) for connection to microphone inputs rated at 19 to 300
2. Disconnect 2-terminal impedance selection socket from rear
ohms and ?High? for connection to high-impedance microphone
of plug element.
inputs.
3. Reconnect 2-terminal impedance selection socket in reverse
Wired for low impedance as supplied. To change impedance,
position so that pin 3 of plug element is inserted in socket ter-
see sections on lmpedance Selection and Connections.
minal ?H? (White).
Output Level (at 1,000 Hz)
4. Reassemble plug element into microphone and seal setscrew
?L??H?
securely by turning out (clockwise).
Open Circuit Voltage* -58.0 dB -35.0 dB
(1.3 mV)(17.6 mV)
*0 dB = 1 volt per Pascal (1 Pa = 94 dB SPL)
?2005, Shure IncorporatedPrinted in U.S.A.
27D3059 (Rev. 10) |
ACEC
