Meeting Topic: Hearing 099
Moderator Name: Greg Dixon
Speaker Name: JJ Johnston, Immersion Networks, AESPNW
Meeting Location: DigiPen Institute of Technology, Redmond, WA
For the April Section meeting, the AESPNW met in the Plato Auditorium at the DigiPen Institute of Technology in Redmond, WA. The meeting featured JJ Johnston presenting an overview at the most basic level of the operation of human hearing. Everything in audio is intended for human hearing, therefore it's clearly helpful to understand just how hearing works. This presentation covered the very basics of the phenomena of human hearing and pointed out some of the mechanics that make it work. Along the way, the meaning of "loudness" as opposed to "power" or "SPL" was made clear, and the need for very different time/frequency resolution at different frequencies stood out.
JJ started off with an overview of the presentation and a nod to the much larger universe of issues related to human hearing. This presentation is really the first of what might eventually be a three-part series, including more "nitty-gritty" detail of the human hearing system and exploration of functional issues around spatial sensation (probably a full day session in and of itself). He took us through the very basic function of human hearing - exploring external acoustics, including HRTF and HRIRs and Interaural Time Differences, the Middle ear and its filter and level control functions, an analysis of the Cochlear system, and the Central Nervous System's contributions involving expectations of what is being heard and perceptual processes and losses.
About our Presenter: JJ Johnston received the BSEE and MSEE degrees from Carnegie-Mellon University, Pittsburgh, PA in 1975 and 1976 respectively.
Most recently he has been working in the area of auditory perception of sound fields, electronic sound field correction, ways to capture sound field cues and represent them, and ways to expand the limited sense of realism available in standard audio playback for both captured and synthetic performances. He was previously employed by Microsoft and then by Neural Audio and its successors. His current status is Chief Scientist of Immersion Networks.
Written By: Dave Tosti-Lane, AESPNW Member at Large