The instrument
Shure's SM57, which was launched in 1965 and is still in production, is one of the most successful microphones. It is a low-impedance cardioid dynamic microphone used extensively in amplified music. It is equipped with the Unidyne III element developed by engineer Ernie Seeler in the late 1950s. That mic element is the engine of the SM58, SM57, 545, and 565. The SM57 uses the same capsule as the SM58.
Details
The SM57 is fitted with an XLR connector and is impedance balanced, which helps to minimize electrical hum and noise pickup when connected to a balanced input. It grille allows for closer placement to the source of sound.Frequency response: 40 to 15,000 Hz
Sensitivity: −56.0 dBV/Pa (at 1,000 Hz)
Impedance: 150 ohms (300 ohms actual) for connection to microphone inputs rated low impedance.