Shure SM58

It is a development of the SM57 microphone, which is another industry standard for both live and recorded music. In both cases, SM stands for studio microphone.

Like all directional microphones, the SM58 is subject to proximity effect, a low-frequency boost when used close to the source. The cardioid response reduces pickup from the side and rear, helping to avoid feedback onstage. There are wired (with and without on/off switch) and wireless versions. The wired version provides balanced audio through a male XLR connector. The SM58 uses an internal shock mount to reduce handling noise. A distinctive feature of the SM58 is its pneumatic suspension system for the microphone capsule. The capsule, a readily replaceable component, is surrounded by a soft rubber balloon, rather than springs or solid rubber. This gives notably good isolation from handling noise; one reason for its being a popular microphone for stage vocalists. Microphones with this feature are intended primarily for hand-held use, rather than on a stand or for instrument miking. The SM58 is unswitched, while the otherwise identical SM58S has a sliding on–off switch on the body. Other suffixes refer to any accessories supplied with the microphone: when a cable is provided, the model is actually SM58-CN, while the SM58-LC has no provided cable (LC means Less Cable); the MVX2U and SM58 bundle consists of the SM58-LC and an inline MVX2U XLR-to-USB signal adaptor (capable of providing phantom power for condenser microphones, and offering an in-built headphone jack for monitoring). The primary difference between the SM58 and the SM57 is the grille. The SM58 is intended for live vocal performances, which tend to put the microphone much closer to plosives. These can stress the diaphragm and distort sound. The rounded grille of the SM58 is lined inside with a thin layer of reticulated foam (open-cell foam) to serve as a pop filter.

Type: Dynamic (moving coil) • Frequency response: 50 to 15,000 Hz • Polar pattern: Cardioid, rotationally symmetrical about microphone axis, uniform with frequency • Sensitivity (at 1,000 Hz Open Circuit Voltage): −54.5 dBV/Pa (1.85 mV); 1 Pa = 94 dB SPL • Impedance: Rated impedance is 150 Ω (300 Ω actual) for connection to microphone inputs rated low impedance • Polarity: Positive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3 • Connector: Three-pin male XLR • Net weight: 298 g

The SM58 and SM57 have been extensively counterfeited. Most of these counterfeit microphones are at least functional, but have poorer performance and do not have the pneumatic suspension. There are many other subtle details which can reveal most of these fakes.