In this guide: The short answer · SM58 · Beta 58A · Nexadyne 8/S and 8/C · Head to head · Output level · Pattern, wedges and feedback · Handling and durability · Which suits which singer · The wireless versions · Common mistakes · FAQ

A band, a venue or a hire company needs handheld dynamic vocal microphones, the shortlist is Shure, and inside it there are three real options: the SM58 every engineer already knows, the Beta 58A that has been the step-up for decades, and the Nexadyne 8 built on genuinely new transducer engineering. All three are good and none are interchangeable. This guide sticks to what Shure publishes, then explains what those figures mean when there is a wedge two feet from the singer.

The short answer

Buy the SM58 for the most forgiving, most universally understood vocal mic there is: guest performers, speech, volunteers, hire stock. Buy the Beta 58A when a singer is fighting a loud stage on wedges and you want a tighter pattern and more output. Buy the Nexadyne 8 for Shure’s current capsule technology and the widest published bandwidth of the three, in your choice of pattern: 8/C cardioid for wide, natural pickup, 8/S supercardioid for maximum rejection of everything else on stage.

Buying one mic you cannot audition? The SM58 is still the lowest-risk purchase in professional audio. Still working out the wider shopping list, dynamic against condenser, handheld against headset? Start with our guide to choosing live microphones.

Shure SM58: the industry default

Shure specifies the SM58 as a dynamic (moving coil) microphone with a cardioid pattern and a frequency response of 50 to 15,000 Hz. The current user guide gives sensitivity at 1 kHz, open circuit voltage, as -56.0 dBV/Pa (1.6 mV), output impedance as 300 ohms and weight as 0.33 kg. Shure’s specification sheet for the same mic quotes -54.5 dBV/Pa (1.85 mV) and 298 g, so treat these as nominal figures.

The response is deliberately shaped, not flat: “tailored frequency response specifically shaped for vocals, with brightened midrange and bass roll off to control proximity effect”. The brightened midrange is why a voice cuts through a guitar amp without much EQ. The bass roll off is there because of the proximity effect, which Shure quantifies: cardioid microphones “progressively boost bass frequencies by 6 to 10 dB below 100 Hz when the microphone is at a distance of about 6 mm”. Roll the bottom off in the capsule and a singer eating the grille sounds full, not muddy.

Shure’s placement table applies to all three mics: lips on the windscreen gives “robust sound, emphasised bass, maximum isolation”, 15 to 60 cm gives “natural sound, reduced bass”. Most complaints about how an SM58 sounds are complaints about distance.

It survives abuse because three things stack up: a pneumatic shock mount isolating the cartridge from the body, a steel-mesh grille over the built-in spherical wind and pop filter, and enamel-coated metal construction Shure lists as “extremely durable under the heaviest use”. The cartridge (R59) and grille (RK143G) are stocked spares, so a dropped mic is usually repairable. The SM58S adds a lockable on/off switch.

Shure Beta 58A: hotter, tighter, fussier about monitors

The Beta 58A is dynamic (moving coil) like the SM58, with two documented differences. The pattern is supercardioid, described in the user guide as “supercardioid, rotationally symmetrical about microphone axis, uniform with frequency”, and Shure states the mic “maintains a true supercardioid pattern throughout its frequency range”. The magnet is neodymium, listed as giving “high signal-to-noise output” and “greater sensitivity and higher output”.

The numbers agree. Output level at 1 kHz is -51.5 dBV/Pa (2.6 mV) in the user guide, or -51 dBV/Pa (2.8 mV) on the spec sheet, against -56.0 dBV/Pa for the SM58. Either way the Beta 58A is roughly 4 to 5 dB hotter for the same sound pressure at the grille. Frequency response is 50 to 16,000 Hz, impedance rated 150 ohms (290 ohms actual) and net weight 278 g.

Both mics use brightened midrange and bass roll off, and Shure describes the Beta’s shaping as ideal for close-up vocals. In practice it reads brighter and more present than a 58: useful on a loud stage, a liability on a sibilant singer through a bright PA.

The tighter pattern is the real reason to choose it, and the usual reason people get it wrong. A supercardioid is narrowest dead ahead and rejects most off the rear quarters, leaving a small rear lobe directly behind. Shure’s guide is explicit: place the monitor loudspeaker “at a 60 degree angle from the rear of the BETA 58A, not directly behind it”. Placed properly it gives usable extra level before feedback; with a wedge dead behind it, a supercardioid can behave worse than the cardioid you replaced.

Nexadyne 8/S and 8/C: what Revonic actually does

Nexadyne is Shure’s current dynamic vocal platform. The two handheld vocal models are the NXN8/S supercardioid and the NXN8/C cardioid, both dynamic (moving coil), and what sets them apart is inside the capsule.

Shure calls it Revonic dual-engine transducer technology, and the user guide explains the mechanism plainly: it “uses two matched transducers to improve microphone performance. The transducers, mechanically identical and electrically out of phase, cancel out unwanted vibrations and provide vivid clarity.” Two elements, wired out of phase, so anything reaching both equally (vibration up the body, handling noise, rumble) cancels, while sound arriving acoustically at the front does not. Shure lists the benefits as “minimised mechanical and handling noise”, “consistent polar pattern, strong off-axis rejection, and reduced stage bleed”, and “authentic, acoustically tuned output that requires less external EQ and signal processing”. On the product page it adds that “hotter output and a cleaner source signal mean more gain before feedback and less corrective EQ at FOH”. Note the wording: less corrective EQ, not none.

The published specifications are the widest here. Frequency response is 50 to 20,000 Hz for both patterns, against 15 kHz for the SM58 and 16 kHz for the Beta 58A. Sensitivity at 1 kHz, open circuit voltage, is -54.0 dBV/Pa for the 8/C and -51.0 dBV/Pa for the 8/S. Output impedance is 300 ohms and 450 ohms respectively, weights 258 g and 294 g. Housing is die-cast aluminium in black with a dent-resistant hardened grille, and both ship with a mic clip and zipped case.

Shure says the 8/C “offers a natural, wide-open sound with a generous pickup area for singers who move between soft passages and full-voice moments”, while the 8/S “delivers a tighter pattern with maximum rejection of cymbal bleed, monitor wash, and crowd noise for performers sharing dense stages”. Same body, same build, different polar response.

Head to head: the published specifications

Output level: what 5 dB buys you

On the user guide figures the Beta 58A (-51.5 dBV/Pa) and Nexadyne 8/S (-51.0 dBV/Pa) are the hottest and effectively level with each other, the 8/C sits in the middle at -54.0 dBV/Pa, and the SM58 is quietest at -56.0 dBV/Pa.

A 4 to 5 dB head start helps in three ways: a quiet singer no longer lives at the top of the preamp’s gain range, so there is less preamp noise in the channel; a long cable run has less chance to add hiss relative to signal; and on desks with modest preamps you work in a better part of the gain structure.

What a hotter mic does not give you is free gain before feedback. Loop gain is set by pattern, response shape, monitor position and the singer’s distance from the grille, so swap a 58 for a Beta and match the fader level and the extra sensitivity is cancelled by the gain you take off at the preamp: the feedback margin comes from the pattern, not the magnet. It is also the classic mid-set trap. Put a hot mic on a channel gained for a quieter one and it howls; the other way round, the vocal disappears.

Pattern, wedges and feedback

Cardioid: SM58 and Nexadyne 8/C

A cardioid rejects most at 180 degrees, straight behind the mic, which maps neatly onto the classic single wedge in front of the singer: from the capsule’s point of view, the wedge sits in the null. The front pickup area is wide and forgiving, so a singer who moves, tilts the mic or drifts off axis loses less level. For guest vocalists, presenters, worship leaders working a stage and school productions, that forgiveness beats a few dB of isolation.

Supercardioid: Beta 58A and Nexadyne 8/S

A supercardioid is narrower at the front and rejects most off the rear quarters, leaving a small rear lobe directly behind. Shure’s guidance for the Beta 58A is a monitor at 60 degrees off the rear rather than dead behind, and the same logic applies to the 8/S. Two wedges angled in from the sides, which is how most bands work anyway, suits a supercardioid well. The payoff is what Shure claims for the 8/S: less cymbal bleed, monitor wash and crowd noise, so a vocal you can push without dragging the kit up with it. The cost is technique, because a tighter pattern loses level faster off axis.

In-ears and spoken word

On an in-ear stage the loudest argument for a supercardioid disappears with the wedges. What is left is drums, backline and crowd, so pattern becomes a question of how much stage you want in the vocal channel, and many engineers go back to cardioid mics because the forgiveness is then free (see our in-ear monitor systems guide). For spoken word, cardioid is almost always the answer: speakers hold microphones badly and talk across the grille, and a wide pattern hides both.

Handling noise, wind and abuse

All three attack handling noise, but differently. The SM58 and Beta 58A use Shure’s pneumatic shock mount, a mechanical suspension isolating the cartridge from the body so knocks and cable-borne rumble never reach the diaphragm. Nexadyne adds an acoustic answer on top: vibration reaching both out-of-phase transducers cancels itself. That is a different mechanism from a rubber mount, and it is the claim Shure leads with for the platform.

On wind and breath, the SM58’s spherical grille is doing real work: Shure calls it a highly effective built-in spherical filter for wind and breath pop noise, and it is one reason the 58 shrugs off close, plosive-heavy vocals. All three take optional foam windshields, worth budgeting for on festival and marquee work.

Durability comes down to grille, body and spares: steel mesh over enamel-coated metal on the SM58, hardened steel mesh over enamel-painted die-cast metal on the Beta 58A, a dent-resistant hardened grille over die-cast aluminium on the Nexadyne. For hire stock the deciding factor is usually spares rather than toughness, and the two older models have decades of stocked cartridges and grilles behind them. That is why so many hire lists still start with a crate of 58s.

Which one suits which singer and stage

Choose the SM58 if

• The mic gets handed to people you have never met: open mics, guests, speeches, karaoke, school and community events.
• You want the response curve every engineer and every desk preset already assumes.
• It is going into hire stock, where cheap spares and a forgiving pattern beat the last decibel.
• A single wedge sits in front of the singer, where a cardioid null wants it, or you need the SM58S switch.

Choose the Beta 58A if

• The stage is loud, monitored on wedges, and you are running out of level before feedback.
• The singer stays on the mic, so a tighter pattern is an asset rather than a trap.
• You want a brighter, more present vocal that cuts through guitars.
• Your wedges sit to the sides rather than dead behind the vocal position.

Choose a Nexadyne 8 if

• You want the widest published bandwidth here and a cleaner starting point at the desk.
• Handling noise is a known problem on your stage or in your fleet.
• You would rather reduce corrective EQ at front of house than sculpt every channel from scratch.
• Then pick the pattern: 8/C for a wide, forgiving cardioid and singers who move between quiet passages and full voice, 8/S for a dense stage with multiple wedges, a drummer within reach and crowd noise close to the front line.

The wireless versions

None of this changes on radio, because Shure’s handheld transmitters take interchangeable capsules. SM58 and Beta 58A handheld configurations run across the BLX, GLX-D+, SLX-D+, QLX-D and ULX-D families, so the capsule you would buy on an XLR is available on a transmitter body.

Nexadyne is in that catalogue too. Shure lists Nexadyne 8/C capsules as RPW200 (black) and RPW202 (nickel) and Nexadyne 8/S capsules as RPW204 (black) and RPW206 (nickel), documented in the same user guide as the wired mics. Published capsule sensitivity is -45.0 dBV/Pa for the 8/C pair and -43.0 dBV/Pa for the 8/S pair, with weights of 155 g and 185 g. Nexadyne-fitted handhelds are available in the SLX-D, QLX-D and ULX-D ranges.

So the system is the long-term platform and the capsule is a choice on top: buy for the RF performance and channel count you need, then fit whichever capsule suits the singer. For the system decision, start with our wireless microphone buying guide or our BLX versus SLX-D+ comparison. Spare capsules live in wireless capsules and bodies in handheld transmitters.

Common mistakes

• Swapping to a hotter mic without resetting gain. Four or five decibels turns a comfortable channel into a squealing one. Re-gain on the new mic, at the distance the singer uses.
• Putting a wedge directly behind a supercardioid. The rear lobe is real, and Shure’s instruction is 60 degrees off the rear.
• Buying supercardioid for people who will not use it properly. Presenters, volunteers and guests do better with a cardioid.
• Judging a vocal mic in a quiet room. All three sound fine alone. The differences are isolation, spill and gain before feedback, none of which exist until the PA and the drummer are running.
• Expecting a capsule to fix a bad stage. Shure claims less corrective EQ for Nexadyne, not none, and no mic fixes a wash-heavy stage or a singer 30 cm off the grille.

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Frequently asked questions

Is the Beta 58A just a better SM58?

No, it is a different tool: hotter by about 4 to 5 dB on Shure’s figures, brighter, and supercardioid rather than cardioid. On a loud stage with sensibly placed wedges that adds up to a better result. Handed to an inexperienced singer, or with a monitor dead behind it, the SM58 can be the better performer.

What is the practical difference between cardioid and supercardioid?

A cardioid has a wide front pickup and rejects most straight behind, which suits a wedge in front of the singer and forgives poor technique. A supercardioid is narrower at the front, rejects most off the rear quarters and has a small rear lobe, so monitors belong off the rear axis (Shure suggests 60 degrees off the rear for the Beta 58A).

What does Revonic dual-transducer technology actually do?

Shure’s user guide describes two matched transducers, mechanically identical and electrically out of phase, so unwanted vibration reaching both cancels while the intended sound does not. The listed benefits are minimised handling noise, a consistent polar pattern with strong off-axis rejection and reduced stage bleed, and output needing less external EQ.

Which of these has the hottest output?

On the current user guide figures, the Beta 58A (-51.5 dBV/Pa) and Nexadyne 8/S (-51.0 dBV/Pa) are level and hottest, the 8/C follows at -54.0 dBV/Pa and the SM58 is quietest at -56.0 dBV/Pa. Treat it as a ranking, since Shure’s spec sheets and guides differ slightly on the older models.

Is the Nexadyne 8 worth the step up from an SM58?

For one singer’s working mic on a busy stage, yes: wider published bandwidth, a cleaner signal at the desk and a different approach to handling noise. For general hire stock, the SM58’s forgiveness, ubiquity and cheap spares are hard to beat.

Which is best for a loud rock stage with wedges?

A supercardioid: the Beta 58A or the Nexadyne 8/S. Both are tighter than a cardioid and both publish higher sensitivity. Keep the wedges off the rear axis rather than dead behind the mic, re-gain the channel, and you should gain usable level before feedback.

Which is best for speech, conference or worship?

Cardioid, so the SM58 or the Nexadyne 8/C. Untrained speakers wander off axis and hold microphones at odd angles, and a wide pattern covers for both. The SM58S adds a lockable on/off switch for lecterns.