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®
THE SHURE 55 SERIES MICROPHONES:
Setting the Standard of Performance
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At any given moment, people in all corners of
the globe are relying upon Shure products to
communicate, entertain, and educate. If you have
an active interest in any sector of the audio world,
chances are you know and trust the Shure name.
Our founder, S.N. Shure, developed our
company around a set of ethical
business principles. The fact
that Shure Brothers has
entered its eighth decade
of continuous opera-
tion is a testament to
the soundness of
these principles.
Though we mourn his
passing, Mr. Shure’s
values and philosophy
remain with us, and are
reflected in the products and
service we provide to our valued customers.
Our associates are trained and truly believe
in Total Quality manufacturing techniques. Our
aim is to design and produce the best products
available for the markets we serve, and to
provide the very best in service worldwide.
Today, we offer a variety of audio products
ranging from wired and wireless microphone
systems to mixers and accessories. Our
components perform in touring sound, broad-
cast, installed sound, and studio recording
applications to name but a few.
Throughout a good part of
our history, one series of pr od-
ucts has remained in our
catalog longer than any
others. Widely recog-
nized the world over,
they have come to be
synonymous with the
name Shure. These
products are the 55
Series of microphones.
In presenting this rich and
fascinating history of the 55 Series,
Shure would like to offer a sincere note of
thanks to all of you who have faithfully stood
with us over the years. Our commitment to pro-
viding you with quality performing products
remains the same now as when the first 55 Series
Unidyne made its debut in 1939.
INTRODUCTION
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Outwardly sleek in design with a futuristic look
well-suited for a 1930s science fiction movie, the 55
Series microphones from Shure have come to symbolize
what many think of when someone says the word
microphone. Following its debut in Shure’s 1939
catalog (#152), the 55 Series embarked upon a path
spanning seven decades which brought it to a point of
professional and public recognition today rarely attained
by any product, let alone a group of audio components.
The visibility of the 55 Series and the permanent
marks it etched on the world’s collective psyche are not
the result of happenstance either. Nor are they the
careful craftings of some slick advertising campaign.
The 55 Series’ benchmark status was earned through
its reputation as a tireless workhorse and dependable
performer, and achieved by its unprecedented audio
quality and reliability.
Shortly after their introduction, the 55 Series
microphones quickly became a mainstay in the world
of audio professionals. Their reputation soon spread
among microphone users as well. Celebrities,
entertainers, and politicians came to rely upon them.
They survived war-time service, and were familiar
fixtures at critical, well-known moments in history.
Scores of photographs, films, and videotapes show
them in the company of kings, queens, presidents, and
generals. They stood in front of Frank Sinatra and
Doris Day during the Big Band era. Elvis embraced
them too (both in person and on a 29-cent stamp issued
in 1994 by the United States Postal Service), as have
countless other rock stars past and present. Today,
some 56 years after their first appearance, 55 Series
microphones are as popular and sought after as ever.
And while the microphones have been subjected to
internal changes
over the years
to keep them
technologically
up-to-date, like
an ageless
beauty, they
still retain the
same external
appearance of
their youth.
Buddy Guy
THE ENDURING BENCHMARK
Admiral Chester W. Nimitz
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Back in
1939, the origi-
nal Unidyne
®
became the first
55 Series offer-
ing. In order to
satisfy as many
microphone
applications as
possible, it was
sold in three
distinct configu-
rations, each of which had a different impedance. The
first, model 55A, utilized a low-impedance design for
operation in 35-50 ohm systems. Model 55B was for
200-250 ohm systems, while the model 55C was built
expressly for use with high-impedance equipment. List
price for the 55A was $42.50 (U.S.), while models 55B
and 55C cost $45. Catalog copy exclaimed that the
microphone incorporated the “very latest in dynamic
microphone design.” It was, after all, “the first high-
quality, low-cost moving-coil type dynamic [microphone]
with true cardioid unidirectional characteristics.” The
Unidyne was built to address problems created by
feedback, background noise, and reverberation.
Sales literature additionally touted the advantages
of cardioid-type true unidirectional microphones, which
“give wide angle coverage with excellent high-quality
response at the front, yet are dead at the rear.”
Verbiage of the time went on to emphasize the ability
of the microphone to “pick up and reproduce the
sound you want as you want it—to discriminate from
unwanted sounds, free from feedback, audience and
background noise, room reflection and reverberation.”
The advantages of the unidirectional microphone
embodied in the original Unidyne remain today as the
solution of choice in many difficult sound pickup and
reinforcement situations.
Utilizing Shure’s proprietary “uniphase” technology,
the Unidyne was marketed for PA, recording, and
broadcast applications. The streamlined chrome head
could be tilted up to 90 degrees. A built-in cable
connector was supplied, as were a special locking
microphone plug attached to the cable, and threads for
stand mounting.
Shure engineer
Benjamin Baumzweiger
is credited with being
the driving force behind
the creation of the first
Unidyne. Baumzweiger
(who later changed his
name to Bauer), began
developing the micro-
phone in early 1937. In
undertaking the project,
HISTORICAL ORIGIN
Famed Shure Unidyne
Dinah Shore
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his primary objective was to create a unidirectional
microphone which used a single dynamic element.
Prior to the Unidyne, the most common way of
creating a microphone with unidirectional response was
to use an omnidirectional (non-directional) element
combined with a bidirectional (“figure-eight” pickup
pattern) element in a single housing. If the outputs
from both cartridges were mixed together electrically in
equal proportions, the results would yield a cardioid
pattern. In fact, you could obtain supercardioid,
hypercardioid, omnidirectional, or bidirectional patterns
simply by controlling
the relative balance
of the two cartridges
with a multi-position
switch or pan-pot.
Unfortunately,
these early dual-
element “unidirec-
tional” microphones
had many drawbacks.
First and foremost,
their size tended to be large and bulky. Performance
was lacking as well. Since the omnidirectional and
bidirectional elements didn’t possess the same
frequency responses, and they were in different
locations in the housing, their resulting combined
frequency response and polar pattern was irregular and
difficult to control. Overall, the concept was far from
perfect, but better than nothing if you were facing
serious feedback or noise problems.
Ben Bauer realized that the best way to deal with
these difficulties was to use just one element. He began
by examining the physics at work. He knew that if a
single element was only exposed to sound on its front
side, you’d obtain an omnidirectional response.
Conversely, a bidirectional microphone has both sides—
the front and back—exposed to sound. With that in
mind, Bauer knew that if he could partially block the
backside of a microphone element, in theory he would
achieve a response somewhere between omnidirectional
and bidirectional which would be heart-shaped, or
cardioid. He set about to create this hypothetical
cartridge, and wound
up with what Shure
would later name
the Unidyne.
When complete,
Bauer’s Unidyne
design was config-
ured so that the
microphone had a
series of front and
rear openings which
allow sound waves to reach both sides of the element’s
diaphragm. The sound waves reaching the diaphragm
from the rear had a longer path and passed through open-
ings which produced a time delay between the sound
entering from the rear and sound waves striking the front
of the diaphragm. By varying the amounts of acoustical
resistance encountered at the rear openings, Bauer was
able to achieve cardioid, supercardioid, or hypercardioid
patterns using a single element, and the first true
unidirectional dynamic microphone became reality.
The Unidyne is part of a Shure microphone tradition.
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An instant
success once it hit
the marketplace,
the original
Unidyne was the
best sounding mic
available, and set a
new standard of
high quality audio
pickup combined
with discrimination
against unwanted sounds. True to Bauer’s design
theories, the directional response was more predictable
and better behaved than its predecessors, so it offered a
tremendous new ability to control feedback and reduce
ambient noise pickup. In addition, its size was small
compared to competitive offerings, thereby making it
popular with singers, entertainers, and public speakers.
During the years between 1939 and 1946, the
Unidyne remained largely the same. Changes to the
line were insignificant for the most part during these
war years, with the most noticeable ones centering
around new model numbers. Variations to the original
design included the 1940 introduction of a separate
broadcast version (model 555), which had an
improved isolation mount. An external call letter
plate and a shroud could be purchased separately as
accessories to this unit.
By 1947, the broadcast version had become model
556, and the three separate models designed for use
with different impedances were replaced with one
single model (model 55) which was equipped with its
own multi-impedance selector switch located under the
case at the rear. Changes were in the offing at the end
of the decade, however, as Ben Bauer prepared to
deliver yet another breakthrough.
“In 1950 we developed a print ad which
dramatically illustrated the dominance within the
industry the Unidyne held around the globe,” Shure
communications consultant Howie Harwood recalls.
“It was titled ‘Used the World Over More Than Any
Other Microphone’ at the top. The subhead read
simply ‘The Microphone That Needs No Name’.
Underneath the headings we ran a large photo of the
Unidyne. The
name or model of
the microphone
didn’t appear
anywhere. The ad
ran in all of the
trade publications.
One of the reasons
we created it was
to demonstrate
how familiar the
Unidyne had
THE MICROPHONE THAT NEEDS NO NAME
Red Skelton
Groucho Marx and Betty Hutton
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become. By that time, it was a microphone which
needed no name or introduction. It was recognized
everywhere.”
At about the same time the print ad first
appeared, Ben Bauer finalized all of the elements
required to put the next generation of Unidynes into
production. First unveiled in 1951, the new “Small
Unidyne” microphones (featuring the Unidyne II
cartridge) improved upon all the features which made
the original
Unidyne such a
success. As their
name implies, the
Small Unidynes
were lighter in
weight and more
compact than the
originals. Compared
to their predecessors
(which were still
offered as “Standard Unidynes” in ‘51), the Small
Unidynes were only about two-thirds the size, and
were available in two model configurations—Model
556 (for broadcast) and Model 55S (for general
purpose). Internally, the new cartridge improved
performance across the board with the addition of
improved magnet materials, diaphragm suspension,
and cartridge isolation. Random noise energy pickup
was reduced even further, while frequency response
was improved as well. Like the Standard Unidynes,
the Small Unidynes were also equipped with a
multi-impedance selector switch.
The new cartridge brought more Unidyne
success to Shure, and carried the marque until 1988,
when it was replaced by a modern cartridge similar to
the one used in the Shure SM48 hand-held musical
and performance microphone. Just as in the time
between the introduction of the original Unidyne and
the advent of the Unidyne II cartridge, the period
between ‘51 and ‘88 saw little change in product
configuration.
Today, the
microphone is almost
outwardly identical
to the 1951 version.
Other than a modifi-
cation made to each
model’s base in 1962,
and the elimination
of the multi-imped-
ance selector switch
in the late ‘70s, the
only other visible changes made were to the material
lining the housing, which started out as reddish-brown
silk in the earliest models, was changed to blue, then
black, and finally to black foam.
Shure’s current catalog shows the 55SH Series II,
which houses the SM48-style cartridge. As
reliable as all of its forebears, the microphone’s
cardioid/dynamic design has even better frequency
response and directional characteristics. It contin-
ues the benchmark tradition of performance and
dependability established with the original
Unidyne.
Indira Gandhi
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For anyone who has read this far, a twofold ques-
tion logically arises: What’s so special
about the 55 Series microphones,
and why do they remain so
popular? “Part of the answer
lies in the fact that they
have become cultural icons,”
answers Shure applications
engineer Tim Vear.
“Technically speaking, they
also had the luck of falling into a
design category which proved to
be the one which won out over
everything else. Carbon and crystal
microphones gradually fell by the
wayside, but dynamic microphones live on.”
One of Shure’s prominent—albeit
unofficial—historians and keeper of corporate
folklore, Vear is an expert on 55 Series facts,
philosophy, and trivia. “With the exception
of some reissues of old Neumann
condenser microphones, I don’t think there
are any other microphones in production
today that go back as far as the 55 Series
models,” he states. “The reality of
having been around for generations has helped make
these products an icon, both internally here
at Shure and to the rest of the world. If
you look around our offices, you’ll find
55 Series pins, engravings, posters,
etched paperweights, and bookends.
The image has even served as a
watermark on invoices. When
people within our industry see a
55 Series microphone, they can’t
help but think of Shure.
Conversely, when someone
outside of the industry sees
one, it serves as a visual cue
which can help transport them to a different
era. Something I refer to as a ‘coolness
quotient’ also adds to the icon status of the
55 Series. Viewed from a design perspec-
tive, they exude all of the coolness of a
‘57 T-bird, Stratocaster guitar, or a James
Dean movie. They are, however, much
more than a symbol. They are real
microphones which adhere to the Shure
tradition of excellence in performance
and quality.”
THE STATUS OF AN ICON
55SH Series II
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INTO THE FUTURE
If the performance of the 55 Series from the
original Unidyne to the model 55SH Series II
available today is any indication, the line is in
good shape to face the audio challenges of the
millennium. The future will most likely find 55
Series microphones still serving a variety of sound
reinforcement needs, and being used in films and
on TV to add realism to scenes depicting events
from the past. Will they still be cool too, in 2002?
Of course. Just look into the polished luster of the
ribbed housing. The answer is right there.
©1996, Shure Brothers Inc.
Written by Greg DeTogne
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By virtue of its status, the 55 Series
has led an exciting life. It helped to
define different eras, and enjoyed front
row seating at noteworthy events of all
description. Some highlights from its
illustrious history include:
The day crooner Rudy Vallee
scrapped his quaint, but old-world
megaphone and switched to a
Unidyne, he became the first
prominent entertainer to adopt the
technology for live performances.
General Douglas MacArthur used Shure
Unidynes on the deck of the U.S.S.
Missouri during ceremonies which
ended the war with Japan in 1945.
You don’t have to look closely to see
the Unidyne in the famous photo of
President Harry S. Truman holding
up the erroneous newspaper headline
reading “Dewey Defeats Truman”.
JFK was frequently photographed
making speeches with a stylish
chrome-plated microphone
stand-mounted in front of him.
Photos of Eva Peron delivering
speeches clearly demonstrate her
microphone of choice. True to
history, the Unidyne also made it
into “Evita”, the Broadway hit
musical based on her life.
HIGHLIGHTS IN UNIDYNE HISTORY
Rudy Vallee
Harry S. Truman
General Douglas MacArthur
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The film “Good Morning
Vietnam”, starring Robin
Williams, made the Unidyne its
virtual co-star. The microphone
was also seen in print ads and
posters for the film across the US.
In 1994, the U.S. Postal Service
issued six stamps which
prominently featured the Unidyne.
One of them was the 29-cent
Elvis stamp.
The list of major entertainers who
used or are still using Unidynes
would probably fill two thick
volumes. Just a smattering of
name-dropping from the complete
list includes Marlene Dietrich,
Dean Martin, Jerry Lewis, Tony
Bennett, Red Skelton, Axl Rose,
Buddy Guy, and Tom Petty.
President John F. Kennedy
Tony Bennett
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®
Shure Brothers Incorporated
222 Hartrey Avenue, Evanston, Illinois U.S.A. 60202-3696
Phone: (800)25-SHURE Fax: (847)866-2279
In Europe, Phone: 49-7131-7214-0 Fax: 49-7131-7214-14
Internationally, Phone: 847-866-2200 Fax: 847-866-2585
http://www.shure.com
Printed in U.S.A. 8/96 5K AL1281
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