545SD Classic Unidyne® Instrument MicrophoneThe predecessor to the SM57, The 545SD Classic Unidyne® Instrument Microphone is a dual-impedance, unidirectional, dynamic microphone.

Shipped connected for low-impedance operation, the 545SD features a silent magnetic reed on/off switch with lock-on option. A favorite for instrument pickup and recording, the 545SD can also be used on lecterns in public address systems.

•545SD-LC Cable not included

•Exceptionally uniform cardioid pattern minimizes feedback
•Selectable dual-impedance operation
•Silent magnetic reed on/off switch with lock option
•Cardioid dynamic
•Frequency response: 50 to 15,000 Hz

Type

Dynamic

Frequency Response

50 to 15,000 Hz

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Polar Pattern

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

Impedance

Dual. Microphone rating impedance is 150 ohms (250 ohms actual) 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 in User Guide.

Output Level (at 1,000 Hz)

	Low		High
Open Circuit Voltage*	-58.0 dB (1.3 mV)		-35.0 dB (17.6 mV)
*0 dB = 1 volt per Pascal (1 Pa = 94 dB SPL)

Polarity

Positive pressure on diaphragm produces positive voltage on pin 2 (with respect to pin 3).

Switch

Built-in magnetic reed on/off switch with lockplate.

Cartridge Shock Mount

Internal rubber vibration-isolator

Swivel Adapter

Positive action, adjustable through 90 degrees from vertical to horizontal, permits easy removal for handheld use, suitable for mounting on stand with 5/8"- 27 thread

Case

Chrome-plated die casting with ARMO-DUR® grille and stainless steel screen

Dimensions

See User Guide

Net Weight (less cable)

255 grams (9 oz)