Kenneth N. Stevens

He died in 2013 from complications of Alzheimer's disease.

Stevens was also active in the IEEE, where he held the rank of IEEE Life Fellow. In 2004, Ken Stevens and Gunnar Fant were the joint first winners of the IEEE James L. Flanagan Speech and Audio Processing Award.

Stevens estimated in 2001 that he had supervised approximately forty Ph.D. candidates.

He was awarded the National Medal of Science from President Bill Clinton in 1999, and the IEEE James L. Flanagan Speech and Audio Processing Award in 2004.

Stevens was a Fellow of the American Academy of Arts and Sciences, a member of the National Academy of Engineering, a member of the National Academy of Sciences, and a 1999 recipient of the United States National Medal of Science.

Research (Hanson, H.M. 1997) has shown there is a difference between how females and males vibrate their vocal folds; there is a greater spread for female glottis, which gives female voices a more breathy quality than male voices.

On the occasion of his receipt of the Gold Medal of the Acoustical Society of America, in 1995, colleagues wrote of Stevens' Speech Group that "during its existence of almost four decades" it "has been outstanding in the support that it has provided to women researchers, many of whom have gone on to populate the upper echelons of research labs throughout the world.". Stevens’ laboratory has been referred to by colleagues as a "national treasure"

Stevens was active in the Acoustical Society of America since his time as a graduate student. He was a member of the executive council from 1963 to 1966, Vice President from 1971–2, and President of the Society from 1976–7. He is a Fellow of the ASA. In 1983 he received its Silver Medal in Speech Communication, and in 1995 he received the Gold Medal from the society.

While on sabbatical at KTH in Sweden in 1962, Stevens volunteered as a participant in cineradiography experiments being conducted by Sven Öhman. Stevens' cineradiographic films are among the most widely distributed; copies exist on laserdisc, and some are available online.

Ken credits Fant with the association between the Linguistics Department and the Research Laboratory for Electronics at MIT. Roman Jakobson, a phonologist at Harvard, had an office at MIT by 1957, while Morris Halle joined the MIT Linguistics Department and moved to RLE in 1951. Stevens' collaborations with Halle began with acoustics, but grew to focus on the way in which acoustics and articulation organize the sound systems of language.

The first doctoral thesis Stevens signed at MIT was that of his fellow student, James L. Flanagan, in 1955. Flanagan started graduate school at MIT in the same year as Stevens, but without a prior master's degree; he earned his M.S. in 1950 under Beranek's supervision, then finished his doctoral thesis under Stevens' supervision in 1955.

Stevens joined MIT as an assistant professor in 1954. He became an associate professor in 1957, a full professor in 1963, and was appointed as the Clarence J. Lebel Chaired Professor in 1977. One of his long-time collaborators, Dennis Klatt (who wrote DECtalk while working in Stevens' lab), said that "As a leader, Ken is known for his devotion to students and his miraculous ability to run a busy laboratory while appearing to manage by a principle of benevolent anarchy."

Stevens defended his doctoral thesis in 1952; his doctoral committee included his adviser Leo Beranek, as well as J. C. R. Licklider and Walter A. Rosenblith. After receiving his doctorate, Stevens went to work at Bolt, Beranek and Newman (now BBN Technologies) in Harvard Square. In the early 1950s, Beranek decided to retire from the MIT faculty in order to work full-time at BBN. He knew that Stevens loved to teach, so he encouraged Stevens to apply for a position on the MIT faculty. Stevens did so, and joined the faculty in 1954.

In November 1949, the office next to Ken's was given to a visiting doctoral student from Sweden named Gunnar Fant, with whom he formed a friendship and collaboration that would last more than half a century. Stevens focused on the study of vowels during his doctoral research; in 1950 he published a short paper arguing that the autocorrelation could be used to discriminate vowels, while his 1952 doctoral thesis reported perceptual results for vowels synthesized using a set of electronic resonators. Fant convinced Stevens that a transmission-line model of the vocal tract was more flexible than a resonator model and the two published this work together in 1953.

Stevens attended college in the School of Engineering at the University of Toronto on a full scholarship. He lived at home throughout his undergraduate years. Though Stevens himself could not fight in World War II because of his visual impairment, his brother was away for the entire war; his parents tuned in nightly to the BBC for updates. Stevens majored in engineering physics at the university, covering topics from the design of motorized machines through to basic physics, which was taught by the physics department. During summers he worked in the defense industry, including one summer at a company that was developing radar. He received both his S.B. and S.M. degrees in 1945.

Stevens had been a teacher since his undergraduate years, when he lectured sections of home economics that involved some aspect of physics. After receiving his master's degree, he stayed at the University of Toronto as an instructor, teaching courses to young men returning from the war, including his own older brother. He was a fellow of the Ontario Foundation from 1945 to 1946, then worked as an instructor at the University of Toronto until 1948.

Kenneth Noble Stevens (March 24, 1924 – August 19, 2013) was the Clarence J. LeBel Professor of Electrical Engineering and Computer Science, and Professor of Health Sciences and Technology at the Research Laboratory of Electronics at MIT. Stevens was head of the Speech Communication Group in MIT's Research Laboratory of Electronics (RLE), and was one of the world's leading scientists in acoustic phonetics.

Ken Stevens was born in Toronto on March 23, 1924. His older brother, Pete, was born in England; Ken was born four years later, shortly after the family emigrated to Canada. His childhood ambition was to become a doctor, because he admired an uncle who was a doctor. He attended high school at a school attached to the Department of Education at the University of Toronto.

For adult males, the resonant frequencies of their subglottal system have been measured (using invasive methods) to be 600, 1550, and 2200 Hz. (Acoustic Phonetics, pg 197, Ishizaka et. al., Crane & Boves). The subglottal resonant frequencies of females are slightly higher due to their smaller dimensions. One non-invasive way of measuring these peaks is to use an accelerometer placed above the sternal notch (Henke) to record the acceleration of the skin during phonation. The vibration would capture the resonant frequencies below the glottis (of the subglottal system).