Classic Unidyne Instrument Microphone

The Shure Classic Microphone Series 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.

→ Exceptionally uniform cardioid pattern minimizes feedback in PA applications
→ Selectable dual-impedance operation
→ Silent magnetic reed on/off switch with lock option
→ Cardioid dynamic

Type	Dynamic
Frequency Response	50 to 15,000 Hz
Polar Pattern	Cardioid (unidirectional)-uniform with frequency, symmetrical about axis
lmpedance	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 highimpedance microphone inputs.Wired for low impedance as supplied. To change impedance, see sections on lmpedance Selection and Connections
Output Level (at 1,000 Hz)	Open Circuit Voltage*; L-58.0 dB (1.3 mV); H -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. To lock switch in the ON position, remove screw on lockplate and turn lockplate 180°. Reassemble and tighten screw
Cartridge Shock Mount	Internal rubber vibration-isolator
Swivel Adapter	Positive action, adjustable through 90° 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
Net Weight (less cable)	255 grams (9 oz)
Frequency response	50 to 15,000 Hz