Shure Beta 57A
A supercardioid workhorse that covers 50 Hz to 16 kHz and holds up to a decade of beer-soaked stages.
Overview
Pick up a Beta 57A and the first thing you notice is the weight. The body is die-cast metal in silver blue enamel, with a hardened, matte-finished steel mesh grille on top. This mic doesn't live in a foam-lined case. Shure built it for professional sound reinforcement and project studio recording, and the grille is designed to take abuse and keep working, which is what you want from something pointed at a snare drum night after night.
It's a dynamic moving-coil design with a supercardioid polar pattern, rotationally symmetrical about the microphone axis and uniform with frequency. That last part matters more than the spec sheet suggests. A pattern that stays consistent across the range means the off-axis rejection you get at 1 kHz is still there at 8 kHz, so a stage monitor bleeding into the back of the mic doesn't suddenly sound bright and phasey. Shure's own documentation says the design maintains a true supercardioid pattern throughout the frequency range, which insures high gain before feedback, maximum isolation from other sound sources, and minimum off-axis tone coloration.
The frequency response runs 50 to 16,000 Hz, and it's a tailored curve, not a flat one. Shure describes it as providing drums, guitars, vocals, and horns with studio-quality sound. That tailoring is why the 57A has a reputation for sounding "finished" straight into a console, without the aggressive EQ carving you'd need on a flatter microphone. Output level is rated at -51 dBV/Pa (2.8 mV) at 1,000 Hz open-circuit. That's a healthy signal for a dynamic, enough to drive a preamp without pushing the gain and dragging noise up with it. The neodymium magnet is the reason for that output, and Shure lists a high signal-to-noise ratio as one of the design's explicit features.
Impedance is rated at 150 Ω, with an actual measured value around 290 Ω, intended for connection to microphone inputs rated low Z. Shure also notes the mic is minimally affected by varying load impedance, so it behaves predictably whether it's plugged into a cheap mixer preamp or a high-end console channel. Phasing follows the standard convention: positive pressure on the diaphragm produces positive voltage on pin 2 with respect to pin 3. The connector is a three-pin professional audio connector, male XLR type.
Proximity effect is where the 57A's grille redesign earns its keep. Like any unidirectional microphone, it progressively boosts bass frequencies by 6 to 10 dB at 100 Hz when placed about 6 mm (1/4 in.) from the source. That's a usable amount of low-end lift, enough to fatten a snare or add chest to a vocal without turning to mud. To keep close-up use from producing explosive low-frequency sound, the bass response gradually rolls off, which gives the user more control over the proximity effect. The completely new grille design, per Shure, lets you take better advantage of that effect than earlier designs allowed.
Shure also built in an advanced pneumatic shock mount system that minimizes transmission of mechanical noise and vibration — the kind of thing you don't appreciate until you're on a hollow stage with a drummer stomping a pedal three feet away. It's a detail that separates the 57A from cheaper dynamics that ring and thump at the slightest provocation.
The application list reads like a working engineer's call sheet. Toms get one mic per drum or one between each pair, placed 2.5 to 7.5 cm (1 to 3 in.) above the heads and aimed at the top heads for medium attack and balanced sound. On double-headed toms, Shure notes you can pull the bottom head and place the mic inside pointing up. Snare gets placed 2.5 to 7.5 cm above the rim of the top head, aimed at the head, for the most "snap" from stick impact, with an optional second mic below the bottom rim for more snare sound. Guitar and bass amps get a range of positions: 2.5 cm (1 in.) from the speaker on-axis with the cone for sharp attack and emphasized bass; 2.5 cm at the edge of the cone for sharp attack and more high frequency; 15 to 30 cm (6 to 12 in.) back and on-axis for medium attack and a full, balanced sound; and 60 to 90 cm (2 to 3 ft.) back on-axis for softer attack with thin, reduced bass. Vocals sit 2.5 to 15 cm (1 to 6 in.) from the mouth for a rich, warm sound. Brass gets 30 to 90 cm (1 to 3 ft.) away, on-axis with the bell. The manual also says microphone technique is largely a matter of personal taste and there is no one "correct" position, which is an honest thing to print in a product manual.
Stage placement gets its own guidance. For maximum rejection of unwanted sound, the monitor or P.A. loudspeaker should sit at a 60° angle from the rear of the mic, not directly behind it.
Shure's advertising in the mid-1990s leaned hard on the Beta line's live-performance reputation. Copy in Mix (1996, p.119) asked what makes Beta microphones the world's most respected for live performance and pointed to the mic's response to vocals and instruments. The same campaign, running in Mix (1996, p.48) and EQ (1996, p.28), stressed the tight, uniform supercardioid pickup patterns and the exceptional gain-before-feedback they allow. That's marketing, but it describes the actual engineering. By 1997, Studio Sound (May 1997, p.44) was describing the Beta line as including "the improved Beta 57A and 58A with smoother response and lower handling noise," which frames the 57A as a refinement rather than a fresh design. A 2004 rebate promotion covered in Pro Audio Review (April 2004, p.2) offered $15 off the Beta 57, Beta 58, and Beta 87.
The 57A is not a studio condenser. It's a dynamic with a tailored curve and a supercardioid pattern, and it does its best work close-up on loud sources where isolation matters. Shure's application notes list drums, guitar amps, brass, woodwinds, and vocals, but the design intent is live sound, where a mic has to survive the truck, the stage, and the singer who drops it.
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