In the past decade, Doug has founded and led two of the fastest-growing tech companies in the music industry.
Darkglass Electronics (acquired by Japanese giant Korg) specializes in distortion pedals, amplifiers and cabinets designed especially for heavy rock bassists. Neural DSP in turn develops digital effects and associated hardware to emulate real guitar and bass amplifiers using latest knowledge of signal processing and artificial intelligence. Both companies became leaders in their niches, with multiple award-winning software and hardware products.
The Ear is not a Fourier Transformer
Richard Heyser was fascinated by the link between time and frequency, via the Fourier and Hilbert transforms. During his lifetime, performing the Fourier transform was a difficult thing to do, and he developed novel techniques to allow us to measure the time and frequency characteristics of audio systems and studios. Nowadays, it is simple to perform Fourier transforms in real-time on readily available computer hardware. Much of our processing of signals in the audio chain is now done via the Fourier transform, and versions of it form the basis of our audio coding systems for audio delivery.
We also know that the inner ear of a human listener converts a time domain acoustic signal into a frequency-based representation before it encodes it into neural impulses. However, the inner ear’s frequency representation is different to that obtained from a Fourier transform.
The talk, which should be accessible to people from all the different areas of endeavor within the AES, will first examine the operation of the ear, including its dynamic non-linear behavior. It will then examine the difference between the Fourier Transform and the human auditory system and highlight how they trade off time and frequency resolution differently.
We will then look at how processing in the Fourier domain can result in artifacts that can be perceived by the ear and discuss how one could mitigate these effects in Fourier-based processing systems.
Finally, we shall look at the unique ways the human auditory system allows us to hear the incredible complexity of the audio signal and how that might affect what we do in the future to improve audio, and perhaps move closer to some of Richard’s final words: “Perhaps more than any other discipline, audio engineering involves not only purely objective characterization but also subjective interpretations. It is the listening experience, that personal and most private sensation, which is the intended result of our labors in audio engineering. No technical measurement, however glorified with mathematics, can escape that fact.”
Jamie Angus-Whiteoak is Emeritus Professor of Audio Technology at Salford University. Her interest in audio was crystallized at age 11 when she visited the WOR studios in NYC on a school trip in 1967. After this she was hooked, and spent much of her free time studying audio, radio, synthesizers, and loudspeakers, and even managed to build some!
She has worked in both industry and academia in diverse fields from integrated optics and acoustics to analogue and digital signal processing. Her expertise ranges from valve (tube) circuits to the applications of esoteric number theory in signal processing. She has pioneered degree level courses in both music technology and electronic engineering in the UK.
She is the inventor of modulated, wideband, and absorbing diffusers, direct processing of Super Audio CD signals, and one of the first 4-channel digital tape recorders. She has done work on signal processing, analogue circuits, diffusers, and numerous other audio technology topics. Jamie has been active in the AES for 31 years, she is a member of the Diversity, Equity and Inclusion, and Education Committees, and is currently VP for the Northern Europe Region. She has also been Papers Co-Chair for several conventions, as well as a judge for the Saul Walker Student Design and MATLAB Student Plugin competitions.
Jamie has been awarded an AES fellowship, the Institute of Acoustics Peter Barnet Memorial Award, and the AES Silver Medal Award, for her sustained contributions to audio, acoustics, and education.