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Louis D. Fielder to Deliver AES Heyser Memorial Lecture

Fielder will deliver a lecture titled “Psychoacoustics Applied to Dynamic-Range and Nonlinear-Distortion Assessment.”

New York, NY (August 20, 2019)—Louis D. Fielder, a leading researcher in the fields of psychoacoustics and audio coding, will deliver the 20th annual Heyser Memorial Lecture at the upcoming AES New York Convention, offering his insights from decades of industry research and development.

Fielder will deliver the lecture, titled “Psychoacoustics Applied to Dynamic-Range and Nonlinear-Distortion Assessment,” on Thursday, October 17 at 6:30 p.m. as part of the Special Events series taking place during the AES New York Convention, October 16–19.

“The psychoacoustics of noise detection, measurements of noise in the digital-audio recording, storage and reproduction chain, and measurements of peak-acoustic pressures in music performances are combined to determine the requirements for noise-free reproduction of music,” begins Fielder’s abstract for the lecture. “It is found that the required ratio between the maximum reproduction levels and the perceived audibility of noise can be as much as 124 decibels. When more practical circumstances are considered, this requirement is shown to drop to more feasible values.”

The lecture will continue by examining how auditory masking allows for the assessment of nonlinear distortions in digital-audio conversion systems operating at low-signal levels, along with examples of digital-audio conversion systems. Fielder’s lecture will conclude with a discussion of expanded use of masking and present a model for determining non-linear distortions in headphones and low-frequency loudspeakers.

Fielder’s industry experience began in 1976 as an electronic component designer for custom sound reinforcement systems at Paul Veneklasen and Associates. In 1978, he became involved in digital-audio and magnetic recording research at the Ampex Corporation.

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His interest in applying psychoacoustics to the design and analysis of digital-audio conversion systems soon led to other career opportunities, including his work at Dolby Laboratories (1984–2018) on the application of psychoacoustics to the development of audio systems and the development of a number of bit-rate reduction audio coders for music distribution, transmission, and storage applications including AC-1, AC-2, AC-3, Enhanced AC-3, AAC and Dolby E.

Additionally, Fielder managed the Sound Technology Research Department at Dolby Laboratories in San Francisco (2005–2009) and has led further research into perceptually derived limits for the performance for digital audio conversion, low-frequency loudspeaker systems, distortion limits for loudspeakers/headphones, loudspeaker-room equalization and headphone virtualization.

Other industry involvement and recognition include his status as a life Fellow of the AES, a recipient of the AES Silver Medal Award, a senior life member of the IEEE, a life member of the SMPTE, and an emeritus member of the Acoustical Society of America. Fielder served on the AES Board of Governors (1990–1992), as AES president (1994–1995) and as AES treasurer (2005–2009).

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The Richard C. Heyser Memorial Lecture series, hosted by the AES Technical Council at each convention, honors the extensive contributions to the Society made by Heyser, who was widely known for his ability to communicate new and complex technical ideas with great clarity and patience.

Audio Engineering Society •