In this world of ever-heightening hyperbole, it is hard to overstate the impact Shure’s classic dynamic microphone models had when they first came out in the Thirties, Forties, Fifties and Sixties of the last century. This impact can still be felt today – the Shure SM57 and SM58 models are continuing to be ubiquitous on stages and in studios all over the globe.

What Shure managed to do then – and continues to do to this day – was to come up with sturdy, yet good sounding mics that put the proverbial show on the road in 1939. And the show still goes on…

Let’s take a look at the history and the features of Shure’s bonafide classics – the 55SH Series II, the 545SD Unidyne III, the 565SD Unisphere I, the SM57, and the SM58.

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By the mid-1930s sound engineers had already come to the conclusion that omnidirectional microphones weren’t really the best tools for live sound applications, due to the high risk of feedback from the PA system. The solution to this problem had also been found already – the unidirectional microphone, or what we now know as the cardioid mic.

The cardioid mic picks up sound from its front, while rejecting most of the sound coming in from the sides and the back. The cardioid pattern is achieved by controlled phase cancellation. In the mid-1930s the only microphones offering a cardioid pickup pattern were either delicate and expensive condenser microphones (with two wafer-thin diaphragms) or cumbersome twin-capsule dynamic models (often combining an omnidirectional moving-coil dynamic with a figure-8 ribbon capsule).

The all-important breakthrough that made Shure’s iconic Model 55 possible was Ben Bauer’s development of the Unidyne-capsule. The moving-coil Unidyne-capsule manages to reject sound from the back by an elaborate system of air vents in the cartridge that lead to the sound from the back travelling to the diaphragm in several different ways, which in turn results in controlled phase cancellation.

Shure’s R & D team also managed to come up with a – for that time – extremely compact and very sturdy cast metal housing with a built-in swivel adapter.

The original Shure Model 55 (today known as the ”Fat Boy” for its larger, rounded housing) was what sound engineers had waited for. Here was a compact mic that gave you superior gain-before-feedback coupled with a very decent sound quality in a sturdy, roadworthy package.

In 1951 the Shure 55 was overhauled with an improved Unidyne II capsule and a smaller housing (55SH).

The current model – the Shure 55SH Series II – was introduced in the late 1980s, and features an updated cartridge (the Unidyne III) and an improved shock-mount for the capsule. It kept the on/off-switch from its predecessor.

Due to the fact that the 55SH was the mic that the young Elvis was often seen with, this iconic Shure is still widely called the ”Elvis mic”.

The Shure 55SH Series II still does have a place as a ”working mic”, besides being used in movies, commercials and music videos, whenever the makers try to delve into vintage chic and panache.

Due to the placement of the cartridge inside the large metal housing the 55SH’s sound is a little bit more mid-centred than more modern dynamic vocal mics. It can also be a tad more sensitive to wind noise and plosives, which has to be taken into account during the placement and use of the microphone.

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By the late 1950s times, styles, musical genres and technology had all moved on, and sound technicians started to ask for even smaller microphones.

A Shure engineer by the name of Ernie Seeler hit the proverbial jackpot by developing the first-ever handheld, end-firing, unidirectional moving-coil microphone.

This new model – introduced in 1959 – was called the Shure 545SD. The 545SD encompassed a whole number of improvements, the most important one being the pneumatically mounted Unidyne III capsule.

The pneumatic shock-mount reduces handling noise drastically, and it made holding the microphone in your hand a realistic option for the first time.

The Shure 545SD is a dual-impedance mic, because back in the late-50s/early-60s there was still plenty of high-impedance audio equipment around. These days it’s mostly Blues harp players, who use the high-Z setting to connect the mic to a guitar amplifier.

Ernie Seeler also came up with an ingenious magnetic on/off-switch that doesn’t pop or crackle in use, and that can also be locked in the ”on” position if desired.

Although the Shure 545SD is seen more as an instrument microphone these days, it was also a very popular choice for singers back in the day. The Beach Boys’ Brian Wilson often chose a 545SD in the studio for his lead vocals during the ”Pet Sounds” and ”Smiley Smile” era.

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Ernie Seeler took things a little bit further with his next design – the Shure 565SD Unisphere I.

The Shure 565SD is based on the 545SD, but adds a sturdy spheric windshield to the design. The built-in pop filter is very easy to replace, should it become seriously damaged.

In addition to improving the 565SD’s resistance to plosives and wind noise, the ball grille also leads to a slightly different frequency response, when compared to the 545SD.

The success of the 565SD has meant that its look has become the gold standard for handheld vocal microphones. Its legendary status is due to the fact that it was chosen as the only microphone model at the original Woodstock Festival. The Shure 565SD was also Freddie Mercury’s preferred live mic (”Aaayeee-oh!”).

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The reason Shure followed up the 545SD with the SM57 so quickly can be found in the popularity of TV in the 1960s.

TV studios loved the sound and compact size of the 545SD, but they disliked the shiny, reflective surfaces of the Shure model, that made lighting a chore.

The Shure SM57 (the ”SM” stands for ”studio mic”) addressed these issues, by providing a mic with the same slim shape as the 545SD, but now clad in a non-reflective, matte dark gray finish. While they were at it, Seeler and his team also did away with the dual-impedance feature – that was unnecessary in the professional TV studio – and with the on/off-switch – that was unwanted in the TV studio. They also fine-tuned the capsule’s detailed specifications.

Again, although the Shure SM57 is touted as an instrument microphone, it also performs very well as a vocal mic. Good examples are many live shows of Status Quo and Motörhead, as well as Peter Gabriel’s use of the SM57 for vocals during the recording of his classic album ”So”.

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The Shure SM58 is to the 565SD what the SM57 is to the 545SD – a slightly redesigned, newer version, made especially for use under TV studio lighting.

The SM58’s body sports the same dark gray matte finish also found on the SM57.

The ball grille has been redesigned to be even sturdier. Its finish is a non-reflective light gray.

The Shure SM58 is a true million-seller that has stood the test of time. This model can be found in most venues all over the globe.

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I’ve prepared a few videos to give you an idea of how these five classics perform.