AES’ second Sound Field Conference ‘breaks new ground’

Over 90 delegates gathered at the University of Surrey in Guildford, UK from 18-20 June for the second international conference on Sound Field Control presented by the Audio Engineering Society (AES).

Chaired by Filippo Maria Fazi and Philip Jackson, the conference broke new ground in the understanding of the active management of audio delivered within an acoustical environment, according to the AES.

Over 30 papers were presented on topics ranging from sound zones through higher order ambisonics, mode matching and psychoacoustics to sound field control theories, microphone arrays and array transducers.

Delegates had ample opportunity to experience demonstrations of sound field control technology including personal sound zones, 3D audio capture and adaptive object-based stereo reproduction. Bruce Drinkwater’s (pictured) invited talk on ultrasonic levitation focused on the new technology that enables small objects to be lifted using ultrasonic “tractor beams” – something that just a few years ago would have seemed like science fiction. He brought along a small demonstrator of the technology that could hold little balls in midair.

Keynote Philip Nelson is professor of acoustics for the Institute of Sound and Vibration Research at the University of Southampton, and a leader of research council activity in the UK. Nelson’s talk on the history of sound field control on the first day illuminated the connections between the active control of sound and contemporary approaches to sound reproduction within the consistent framework provided by multichannel digital signal processing and the physical behaviour of linearly superposed sound fields.

The Day Two keynote speaker was Gary Elko, president of mh acoustics. With Jens Meyer, Elko developed the Eigenmike, a spherical microphone array that decomposes the sound field into a compact set of orthogonal spherical harmonic signals. The Eigenmike is now gaining commercial interest in the field of immersive audio. In his keynote address, Elko offered delegates a comprehensive review of differential microphone array technology. Steven van de Par then reviewed the effects of reverberation on auditory perception, concluding with a description of a system for reproducing the most perceptually important parameters of direct and reflected sound in a room that already has its own reverberation.

Themes of the conference, arising out of workshop discussions and informal interactions, coalesced around the different forms and meanings of the broad term “sound field control,” and how it both includes, but is broader than, spatial audio. Delegates seemed particularly interested in how to design systems to engineer an intended user experience, one that possibly follows people around as they move, and adapts to their circumstances, as well as being useful for multiple listeners. There was talk of navigable sound fields that can only be experienced by exploring them, which connects strongly to the growing importance of virtual reality. 

Event attendees also appeared enthusiastic about the prospect of a third Sound Field Conference in ‘a few years’ time’.