The predecessor to the SM57, The Shure 545SD Classic Unidyne Instrument Microphone is a dual-impedance, unidirectional, dynamic microphone.
Shipped connected for low-impedance operation, the Shure 545SD Mic features a silent magnetic reed on/off switch with lock-on option. A favorite for instrument pickup and recording, the Shure 545SD Microphone can also be used on lecterns in public address systems.
Shure 545SD Microphone Specs:
50 to 15,000 Hz
Cardioid (unidirectional)--uniform with frequency, symmetrical about axis
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: Open Circuit Voltage* -58.0 dB (1.3 mV)
HIGH: Open Circuit Voltage* -35.0 dB (17.6 mV)
*0 dB = 1 volt per Pascal (1 Pa = 94 dB SPL)
Positive pressure on diaphragm produces positive voltage on pin 2 (with respect to pin 3).
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
Chrome-plated die casting with ARMO-DUR grille and stainless steel screen
Net Weight (less cable)
255 grams (9 oz)