General

UNIDYNE® III MODEL 545SD User Guide

The UNlDYNE® III Model 545SD is a dual-impedance, unidirectional, dynamic microphone. Shipped connected for low-impedance opera- tion, it features a silent magnetic reed on/off switch.

The UNlDYNE III is a favorite for instrument pickup and recording, and can be used on lecterns for public address systems such as those used in political conventions and legislatures, convention halls, hotels, public auditoriums, stadiums, schools, and churches.

FEATURES

•Exceptionally uniform cardioid pattern minimizes feedback in PA applications

•Selectable dual-impedance operation

•Silent magnetic reed on/off switch with lock option

•Cardioid dynamic

•Frequency response: 50 to 15,000 Hz

CONNECTIONS

when using the microphone with a balanced input, pins 2 and 3 are the audio signal carriers. When using the microphone with an unbalanced input, use a cable wired with pin 2 as the signal carrier and pin 3 connected to the cable shield (ground), such as the Shure C20HZ high-impedance cable.

IMPEDANCE SELECTION

The microphone is shipped connected for low impedance operation. To change to high impedance, proceed as follows (refer to Figure 1):

1.Remove plug element at receptacle end of microphone by turning slotted setscrew in (counterclockwise) and carefully withdrawing plug element from case.

2.Disconnect 2–terminal impedance selection socket from rear of plug element.

3.Reconnect 2–terminal impedance selection socket in reverse position so that pin 3 of plug element is inserted in socket ter- minal “H” (White).

4.Reassemble plug element into microphone and seal setscrew securely by turning out (clockwise).

SET SCREW

PLUG ELEMENT

IMPEDANCE SELECTION SOCKET	PIN 3

IMPEDANCE SELECTION-

RECEPTACLE END OF MICROPHONE

FIGURE 1

POLARITY

All cables and microphones should be tested to ensure that they have the same polarity. To test two microphones and/or their cables for proper polarity, 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 the sound drops drastically, or if a dead spot is found when talking between the two microphones, either the microphones or their cables have opposite polarity.

To change the polarity of a microphone cable, either use a Shure A15PRS phase reverser or interchange the wires connected to pins 2 and 3 of the three-pin connector at one end of the cable. To change the polarity of a microphone, the microphone cartridge leads must be interchanged. This should be performed by your dealer, the Shure Factory Service Department, or other qualified service personnel.

SPECIFICATIONS

Type

Dynamic

Frequency Response

50 to 15,000 Hz (see Figure 2)

Polar Pattern

Cardioid (unidirectional)-uniform with frequency, symmetrical about axis (see Figure 3)

lmpedance

Dual. Microphone rating impedance is 150 ohms (250 ohms ac- tual) for connection to microphone inputs rated at 19 to 300 ohms and “High” for connection to high-impedance microphone inputs.

Wired for low impedance as supplied. To change impedance, see sections on lmpedance Selection and Connections.

Output Level (at 1,000 Hz)
“L”	“H”
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 Incorporated		Printed in U.S.A.
27D3059 (Rev. 10)

545SD specifications

The Shure 545SD is a dynamic microphone renowned for its rugged durability and exceptional audio quality, making it a go-to choice for professional musicians and audio engineers alike. This microphone, which was first introduced in the 1960s, has stood the test of time and remains a staple in both live performance and studio settings.

One of the standout features of the Shure 545SD is its tuned frequency response. Designed with an emphasis on clarity, this microphone produces a clean and natural sound that excels in capturing vocals and instruments. Its frequency response ranges from 50 Hz to 16 kHz, providing a rich low-end presence while maintaining crisp highs. This characteristic makes it particularly well-suited for applications ranging from speech to singing, allowing users to achieve a balanced sound across various vocal types.

Another notable technology incorporated in the 545SD is its cardioid polar pattern. This design minimizes background noise and feedback by capturing sound primarily from the front of the microphone while rejecting sound from the sides and rear. This characteristic is particularly valuable in live settings where stage noise can interfere with the clarity of the performance, as it allows the artist's voice or instrument to shine through without unwanted interference.

In terms of build quality, the Shure 545SD features a robust metal construction that ensures durability and longevity. This resilience is essential for touring musicians who require a reliable microphone that can withstand the rigors of travel and frequent use. Additionally, the microphone is equipped with a shock mount system that reduces handling noise, further enhancing its performance in dynamic environments.

The Shure 545SD also includes a detachable cable, allowing for easy replacement and versatility in various settings. The microphone's design is not only functional but also aesthetically pleasing, featuring a classic appearance that has become synonymous with professional audio gear.

Overall, the Shure 545SD is a dynamic microphone that blends exceptional sound quality, durability, and user-friendly features. Its long-standing reputation in the industry speaks to its effectiveness and versatility, making it a dependable choice for artists and audio professionals. Whether on stage or in the studio, the 545SD continues to deliver a listening experience that is both clear and impactful, upholding its legacy as a timeless microphone.