50 Years in the Making: The Rise of the Mighty SM7B
In 2023, Shure is celebrating the 50th anniversary of a microphone that has gained worldwide popularity among musicians, podcasters and streamers alike. Join Shure historian MICHAEL PETTERSEN as he enters the company archives to uncover the secrets it holds about the rise of the mighty SM7B.
Back to the Roots
The SM7 story really begins with the SM5 broadcast microphone – a unidirectional dynamic boom mic introduced in 1964 that was designed for television and film studios. It was a beast, measuring over 10” in length and weighing in at a hefty two pounds.
In the late 1960s, Shure set out to develop a new microphone designed especially for recording studios, radio stations, and voiceover work.
According to lore, the development of the SM7 went something like this: A group of Shure microphone engineers started with the Unidyne III SM57 element and transformed it into a voiceover mic.
The SM7 microphone made its debut in 1973.
Genesis of the SM Line
In 1963, Shure professional products market manager Bob Carr proposed a new line of microphones designed for radio, television and film studios.
The SM (Studio Microphone) line was based on existing mic models, but offered new features designed for studio use. These included a dark non-reflective surface for television studio use, a three-pin male XLR connector, and dual low impedance. On/off switches were eliminated or concealed behind a metal plate to prevent the mic from being accidentally muted when in use.
In 1964, the SM line was introduced; it included the SM5, SM33, SM50, SM56, and SM76. In 1965, the SM57 was added and a year after that, the SM58®. Several of these microphones, notably the SM57 and SM58®, found a home on stages for live performance where they dominate to this day.
The SM7, added to the line in 1973, immediately lived up to its birthright as a studio mic.
Gerry Plice and the Design Patent
Gerry Plice, a microphone development engineer, gets credit for the striking and highly recognizable industrial design of the SM7. This was unusual, since a development engineer traditionally creates the transducer inside a microphone, with the exterior enclosure being handled by a design engineer or an outside design firm.
Yet it was Gerry, untrained in industrial design, who fashioned the look of one of the most iconic Shure microphones. In November 1974, US Design Patent 233,669 was issued to Gerald W. Plice, Morton Grove, Illinois, for “Microphone.”
Variation on a Theme
The Shure Unidyne III cartridge is the engine in many Shure moving coil dynamic microphones, including the SM57, SM58®, and SM7. There are, however, some important differences in the SM7 cartridge design.
As a mic designed for broadcasting and voiceover work, the SM7 diaphragm is optimized for increased low-end response by being thinner, and therefore more flexible. The housing of the SM7 allows for a larger volume of air behind the cartridge, which also extends its voice-friendly low-end response.
To increase the output level, the voice coil employs a smaller diameter of wire and has three times as many turns as an SM57 or SM58 voice coil. The thinner diaphragm and heavier voice coil affect the natural resonance frequency of the SM7. All these factors combine to provide the rich low-end response preferred by voiceover artists.
Frequency Switch an Exclusive
One of the features of the SM7 that distinguishes it from many other vocal microphones, in is its variable frequency filter switches. These filters were inspired by the A15 series of adapters.
In 1969, Shure introduced six in-line audio adapters dubbed the A15 Series of Problem Solvers. The larger housing of the SM7 made it feasible to include two A15 functions:
- The A15HP (High Pass) filter attenuates [reduces] bass frequencies below 300 Hz.
- The A15RS (Response Shaper) attenuates treble frequencies above 1,000 Hz.
Two slide switches on SM7 rear panel enable or disable the equivalent A15HP and A15RS circuits. A metal cover plate is provided to hide the switches if desired. This gives the mic four different frequency responses curves – flat, bass roll-off, presence boost, and bass roll-off/presence boost.
With this feature, broadcast stations were able to match the microphone’s frequency response to the vocal characteristics of specific announcers or voiceover talent.
To hear the differences in the SM7B frequency response settings, check out the audio samples (around 10:24) in this Twenty Thousand Hertz podcast episode.
The Evolution of Target Markets
Directed at recording engineers, this ad took its cue from a Top 40 hit of the era, “Whatcha See is Whatcha Get” by The Dramatics. The advertising message focused on the Visual Indication Response Tailoring System, “something you’ve never seen before”, and the four-way frequency filters.
Shown boom-mounted and stand-mounted, the Shure Professional Products catalog stated that the SM7 was “field-tested in recording and scoring stages over a period of seven years to be the finest professional unidirectional dynamic mic ever”. Recording engineers may have agreed, but sales remained flat.
Another print ad suggested that almost every radio station in the country was using a Shure mic. This was hopeful at best as there were about 2,000 US commercial radio stations operating in the 1970s. The SM7 would have flown to the top of the sales charts if every radio station owned one.
By 1980, the SM7’s reach had not extended much beyond radio stations and recording engineers. It remained a best-kept secret among recording engineers and in spite of its innovative attributes, continued to languish in the SM microphone line.
Then and Now
When the SM7 was introduced in 1973, the U.S. retail price was $257 or $1,741 in current US dollars. Today, the MSRP of the SM7B is not $1,741, but only $399.00.
While there have been material and manufacturing changes over its long history, there have also been performance improvements. The SM7 was replaced in 1999 by the SM7A which offered a more efficient humbucking coil to counteract computer monitor noise. The SM7B replaced the SM7A in 2001, adding a larger accessory windscreen.
Social Media Influencer
The SM7B has achieved a level of popularity and buzz that give it legendary status. Mic enthusiasts can hardly visit an audio gear forum without reading pages of animated and sometimes worshipful commentary on the SM7B. It’s also the subject of many a YouTube video.
There’s even a Shure SM7 joke thread out there with posts like these:
“You know that voice in your head that tells you right from wrong? Well, it was recorded with an SM7B.”
“They say with careful positioning, you can use an SM7B to record the future.”
Future So Bright
From 1973 until 2008, SM7 sales crept along, not a best seller, but good enough to keep.
In the 1980s, there had been a small boost in sales associated with recording engineer Bruce Swedien’s use of the SM7 for Michael Jackson’s vocals on Thriller. The significant spike, however, occurred nearly 25 years later when podcasters discovered the SM7B. Sales have continued to climb ever since.
Fifty years after its debut, the SM7B is more popular than ever with engineers, performers, content creators, broadcasters, gamers and streamers. Unit sales are many times greater than its 1970s level, making it one of the company’s best-selling microphones.
After 50 years, the SM7B is finally receiving the respect it deserves.
Let an end user have the final say: “I worked in radio for 36 years and the best microphone I ever used was the Shure SM7. Nothing else was close.”