The UNIDYNEŽ III Model 545SD is a dual-impedance, unidirectional, dynamic microphone. Shipped connected for low-impedance operation, it features a silent magnetic reed on/off switch.
The UNIDYNE III is a favorite for instrument pickup and recording, and can be used on lecterns for public address systems such as those used in political conventions and legislatures, convention halls, hotels, public auditoriums, stadiums, schools, and churches.
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)
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)
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
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-DURŽ grille and stainless steel screen
Net Weight (less cable)
255 grams (9 oz)