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
Type
Dynamic
Frequency Response
50 to 15,000 Hz
Polar Pattern
Cardioid (unidirectional)--uniform with frequency,symmetrical about axis
Impedance
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)
Polarity
Positive pressure on diaphragm produces positive voltage onpin 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 verticalto horizontal, permits easy removal for handheld use, suitable for mounting onstand with 5/8"- 27 thread
Case
Chrome-plated die casting with ARMO-DUR grille andstainless steel screen
Net Weight (less cable)
255 grams (9 oz)