Louis Challis

Louis Aron Challis AM (20 July 1936 – 3 June 2017) was an Australian acoustical engineer known for his work in architectural and environmental acoustics, including the acoustic design of major public buildings and infrastructure projects in Australia and overseas, and for his role in the development of the audio-tactile pedestrian crossing signal system used in Australia and other countries.

Early life and education Challis was born in Sydney on 20 July 1936. Early in his career, he worked at the Royal Australian Naval Research Laboratory at Rushcutters Bay and later at the Overseas Telecommunications Commission. The system combined an audible signal with a tactile vibration, allowing pedestrians who were blind, deaf, or deafblind to determine whether the crossing was showing a walk or do not walk phase by sound or touch. His design also provided for the audible signal to attenuate automatically at night in response to background noise levels, reducing disturbance to nearby residents.

He also contributed to Australian acoustical standards and environmental noise testing methodologies, and served as a specialist adviser in acoustics and forensic audio matters for government agencies. He served in the Royal Australian Air Force Reserve as a specialist adviser in acoustics and held the rank of wing commander.

Honours Challis was elected a Distinguished Corresponding Member of the Institute of Noise Control Engineering of the United States in 1993, became an Honorary Fellow of the Institution of Engineers Australia in 1998, was elected a Fellow of the Australian Academy of Technological Sciences and Engineering in 2000, and received the Centenary Medal in 2001.

In the 2005 Australia Day Honours, he was appointed a Member of the Order of Australia for service to engineering as a pioneer in environmental and architectural acoustic engineering, particularly the development of noise standards, acoustic planning and design of landmark buildings, and advancements in environmental noise testing.

In 2015, the University of Sydney awarded him the honorary degree of Doctor of Engineering (honoris causa).

Death Challis died on 3 June 2017.