The 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.
The classic 545SD Unidyne® remains popular due to its smooth cardioid response and unparalleled dependability. Its lockable, silent magnetic reed on/off switch makes it ideal for unattended sound systems.
Uniform cardioid pattern
Selectable dual-impedance operation
Lockable on/off switch
50 to 15,000 Hz
Cardioid (unidirectional)--uniform with frequency,symmetrical about axis
Dual. Microphone rating impedance is 150 ohms (250 ohmsactual) for connection to microphone inputs rated at 19 to 300 ohms and"High" for connection to high-impedance microphone inputs. Wired forlow impedance as supplied. To change impedance, see sections on lmpedanceSelection 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 onpin 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 verticalto horizontal, permits easy removal for handheld use, suitable for mounting onstand with 5/8"- 27 thread
Chrome-plated die casting with ARMO-DUR grille andstainless steel screen
Net Weight (less cable)
255 grams (9 oz)