Shure SM58

Key specs:

About

The SM58 almost didn't happen the way it did. Its core technology, the Unidyne III capsule, was developed by Shure engineer Ernie Seeler in the late 1950s, continuing a lineage that traced back to Ben Bauer's original 1939 Unidyne, the first single-element unidirectional (cardioid) microphone. Seeler tested the finished design by dropping it, cooking it, freezing it, and submerging it in salt water, engineering it to survive far rougher handling than any studio microphone of the era was expected to face. That same capsule became the basis for both the SM57 (1965) and, a year later, the SM58 (1966), designed and marketed initially for broadcast studio use, not live performance.

Broadcast studios weren't especially interested. Radio and TV stations already had an entrenched competitor, and by most accounts sales of both models were sluggish enough that Shure considered discontinuing the line entirely. What changed their fortunes was a shift in target market: a Shure sales manager suggested pitching the mics to live sound engineers in Las Vegas instead. They caught on quickly there, and within a few years had become the default vocal microphone at major live events, including Woodstock, where Shure's Unidyne III-based models were used almost exclusively across the entire PA system.

Ironically, the trait that made the SM58 famous was one its own designer considered a flaw. Seeler wanted the Unidyne III's frequency response to be flat, and was reportedly unhappy with the rising "presence peak" the design produced in the upper midrange.* That peak, roughly in the 4–10 kHz range, is exactly what gives the SM58 its signature ability to cut through a loud stage mix, and it's a large part of why the mic became indispensable rather than merely reliable. The SM58 has been in continuous production, essentially unchanged, since 1966, making it one of the longest-running products in professional audio.

Notable for: One of the best-selling microphones in history and the de facto standard for live vocal performance worldwide, found in nearly every venue, from small clubs to stadium tours. Renowned for near-indestructible build quality, with widely repeated stories of units surviving drops, being run over, and years of touring abuse without failure. One SM58 capsule design is even used aboard the International Space Station.

Applications

Examples: Live vocals, spoken word and broadcast, podcasting, guitar amp cabinets, brass and horns, and general-purpose close-miking in loud or rugged environments.

Live vocals are the SM58's core purpose and still its most common use worldwide. Its cardioid pattern rejects sound from the sides and rear, reducing feedback and stage bleed in loud environments, while its built-in spherical grille and pneumatic shock-mount handle wind, plosives, and handling noise well enough for aggressive handheld use without a separate pop filter or shock mount. The presence peak helps a vocal cut through a dense band mix without needing much EQ.

For podcasting and spoken word, the SM58's rejection of off-axis and background noise, combined with its rugged build and low cost relative to condenser alternatives, makes it a common and forgiving choice for less-than-ideal recording environments, at the cost of the added detail and top-end extension a condenser mic like the U87 or C414 would capture.

As an instrument mic, the SM58 sees regular use on guitar amp cabinets and brass, where its midrange emphasis and built-in high-SPL tolerance (a natural consequence of the dynamic design rather than a published spec) let it sit close to loud sources without strain, though the SM57, sharing the same capsule in a lower-profile housing, is generally preferred for close instrument work specifically because of its shape rather than any difference in sound.

The SM58's low cost and exceptional durability also make it a default choice anywhere a microphone needs to survive rough handling with minimal maintenance: touring rigs, houses of worship, conference rooms, and any setting where reliability matters more than tonal nuance.

* Glossary - In plain terms: 

• a "presence peak" is a natural boost in output around the upper-midrange frequencies that most cardioid dynamic mics produce as a side effect of their internal geometry, not something deliberately added electronically. Seeler saw it as an inaccuracy because it made the mic's response less flat and neutral. In practice, that same boost is what makes a vocal sound clear and forward through a loud PA system, which is why what one engineer considered a flaw became the industry's most widely used vocal sound for the following six decades.