|
Items in cart [1] |
Questions? Call 888-624-8373 |
| Copyright © 2009. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 177
HUGH S
.
KNOWLES
1 904-1 988
BY EUGENE F
. MURPHY
HUGH SHALER KNOWLES, physicist and consulting engineer
famous for miniaturization of high-quality microphones and
receivers, died in his sleep April 2l, 198S, at the age of
eighty-three. His work at Jensen Manufacturing Company
contributed to early development of high-fidelity loudspeakers
for indoor and outdoor use. He formed and headed until
his death his own firms, notably Industrial Research Prod-
ucts, Inc. from 1946, and Knowles Electronics, Inc. from
1954, emphasizing successive reductions in size of high-
quality transducers. He was active in national and international
standardization, an officer and award recipient of profes-
sional societies, a wise adviser to government, and a generous
supporter of basic and clinical research in hearing prob-
lems. He was widely aclmired for integrity and astute judgment.
Hugh Knowles was born in Hynes, Iowa, September 23,
1904, and spent much of his early years in Mexico, where
his father was a mining engineer. His fluency in Spanish,
French, and German was very useful in his business and
standardization activities. After graduating at the age of
fourteen from high school in San Antonio, Texas, he attended
Alabama Polytechnic Institute in 1920 and 1921 and served
as a radio operator on various ships from 1921 to 1924. By
working as a department editor for Popular Radio, associate
radio editor for the New York Herald Tribune, and receiving
177
OCR for page 178
178
MEMORIAL TRIBUTES
a scholarship in radio engineering, he attended Columbia
University, receiving an B.A. (professional option) in 1928.
He married Josephine Knotts that year. He was a graduate
student in physics at the University of Chicago from 1930
to 1934 and a lecturer in graduate physics there from 1935
to 1936. He received an honorary doctor of science degree
from Northwestern University in 1982.
With a growing family in the depression years, Hugh be-
gan work as an engineer at Jensen in 1931, becoming chief
engineer and vice-president, and remaining to 1950. He
was credited with the first permanent-magnet moving-coi]
loudspeakers, two- and three-way speaker systems, and the
"bass reflex" vented loudspeaker enclosure improving low-
frequency response.
He started, part time, his own consulting engineering
practice in 1936, considered himself a consulting engineer,
and was a registered engineer in Illinois from the initiation
of that program in 1947. Forming Industrial Research Products
in 1946 for research and development on a variety of products,
he served as its president and director of research. After
serving for years as president of Knowles Electronics, specializing
in manufacturing hearing aid transducers, he became chairman
of its board as well, and then relinquished his presidential
responsibilities shortly before his death. Similarly he was
president or chairman of subsidiaries in England and Taiwan
and of other interests in Illinois.
Knowles was elected to the National Academy of Engineering
(NAE) in 1969. He had already served in 1950-1951 as a
member of the Physical Science Division of the National
Research Council.
Most of his advisory services, though, were directly to the
government. During and shortly after World War IT he
worked on blast-resistant loudspeakers for Navy ships, bullhorns
for aircraft carriers, and fuzes for artillery and antiaircraft
shells. From 1948 to 1950 he chaired the acoustics panel
of the U.S. Department of Defense Research and Develop-
ment Board.
OCR for page 179
HUGH S. KNOWLES
179
His miniaturized microphones and receivers were used
for lightweight headsets for astronauts, among many other
applications. Knowles was Proust that the National Aeronautics
and Space Administration accepted his routinely stringent
quality assurance. However, the Bolt Commission investigating
the gap in President Nixon's tapes recorded in the Oval
Office found a small hole in the President's desk leading
to a plastic tube and a Knowles microphone so badly misapplied
that it contributed to the poor a quality of the tapes!
His broad interest in fundamental as well as applied aspects
of acoustics led Knowles to emphasize the need for better
measurements of loudspeakers, of parameters of the human
head at a range of frequencies in relation to bone conductor
hearing aids, and of the acoustic impedance of the ear
canal plugged by the receiver. He repeatedly urged more
realistic methods of measuring hearing aid performance
than the usual free-fielc} tests of microphones and the con-
ventional two-cubic centimeter coupler for the receivers.
To simulate use on an average person, he led development
of KE MAR, or Knowles Electronics Manikin for Acoustic
Research, a full-size head and upper torso with choice of
one or two ZwisIocki couplers mounter} at the eardrum
positionks). Nearly three hundred copies are used in many
laboratories here and abroad in hearing aid and other studies.
Knowles was particularly pleased that he had contributed
to the development of high-quality head-mounted hearing
aids, marked improvements over the multipiece body-worn
sects still routinely user} after World War IT. These earlier
aids benefited from the printed circuits developed for proximity
fuzes, and by 1953 from early transistors, which replaced
the large "peanut" vacuum tubes that required more energy
and both A and B batteries (usually in a separate pack).
However, the users still carried them in a shirt pocket or
special undergarment with a cord to the earphone.
Knowles mounted his small microphone and receiver,
with impedances compatible with transistors and a transistorized
printed circuit, in a thickened eyeglass temple with a short
OCR for page 180
180
MEMORIAL TRIBUTES
plastic tube leading to an earmold. This arrangement im-
mediately removed dangling cords, cord breakage, and noise
from clothing brushing over a microphone. Many patients
wore two aids, over-coming the shadowing of sounds from
the opposite side of the head, and localizing sound sources
more rapidly. Aids were then mounted behind the ear, in
the ear, and finally completely inside the ear canal" thus
achieving an old goal.
Knowles did not attempt to manufacture or market hearing
aids. Because his transducers were used by nearly all American
manufacturers ancl some abroad, he was in constant touch
with the entire industry and aware of its trends. Although
he did not publicize this role, he was a very valuable mem-
ber of the Veterans Administration's advisory committee
on hearing aids performance. With his scrupulous integrity,
he never betrayed commercial secrets. He provided selfless,
impartial, and invaluable insights; broad knowledge of acoustics
and of hearing aid measurements; and precise wording of
controversial issues.
While at Jensen, Knowles was a member and eventually
president of the Radio Engineers Club of Chicago, practically
an honorary society of chief engineers. He was a fellow,
president, honorary member, and Gold Medal recipient of
the Audio Engineering Society; a fellow, president, and Silver
Medal recipient in engineering acoustics of the Acoustical
Society of America; a fellow and national chairman of the
Institute of Radio Engineers (IRE) audio group (predeces-
sor of the present Acoustics, Speech, and Signal Processing
Society of the Institute of Electrical and Electronics Engineers);
and a member of the IRE board of editors for fifteen years.
He was the first American to receive the Alexancler Graham
Bell Award of the Hearing Aid Society of Germany. Though
considering himself an engineer, he was a member of the
governing board of the American Institute of Physics and
of its executive committee.
Hugh Knowles had a long and distinguished service in
standards, starting as chairman of an Acoustical Society of
America Electroacoustics Committee from 1938 to 1941.
OCR for page 181
HUGH S. KNOWLES
18
He was a member of the American Standards Association
(now ANSI) Acoustical Standards Board. Long a member,
for years he headed, the United States delegation to the
International Electrotechnical Commission TC29, emphasizing
engineering matters. Also, he chaired the International
Standards Organization Committee TC43, concerned with
psychoacoustical matters.
Knowles was the author of major chapters on loudspeakers,
telephone receivers, and microphones for three engineering
handbooks and of many technical articles. He held more
than fifty patents.
Hugh and Josephine had three children, James, Margaret
(Mrs. Schink), and Katherine (Mrs. Strasburg). Josephine
ctied in 1969. Hugh later married a cousin, Nancy K Knowles,
with whose family he had maintained close contact since
childhood.
Hugh was among the first donors to the NAE. He was
always a very generous donor, particularly to the Acoustical
Society of America, international standards activities, and
academic acoustics programs. The Knowles family and
companies, continuing and expanding Hugh's long gener-
osity to Northwestern University in support of the audiology
program headed by Raymond Carhart, established the Hugh
Knowles Center for Clinical and Basic Science in Hearing
and Its Disorders. Unfortunately Hugh died just before
the dedication ceremony. The gifts ant} bequest support a
substantial part of the basic research and teaching in audiology
at the Center. The Center includes the Leadership Fund,
the Hugh Knowles Prize, and two chairs focusing on the
relation of audiology to medicine and to engineering.
Colleagues routinely describe Hugh Knowles as very
honorable, a great friend, modest, demancling of himself
as well as of others, a wonderful man to work for, very kind
and thoughtful of others, generous, discreet, meticulous in
choice of words, and tactful. Those who knew him mourn
his loss. Millions of hearing aid users benefited from his
work. The world needs more like him.
OCR for page 182
Representative terms from entire chapter:
hugh knowles
