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22nd AES UK Conference

Illusions in Sound: the application of psychoacoustics to audio

11-12 April 2007, New Hall, Cambridge

Wednesday 11th April 2007

09:45 to 18:00

09:45           Introduction

John Dawson, Conference co-chair

10:00           Psychoacoustic insights in audio system design

J Robert Stuart, Meridian Audio Ltd.

In order to design audio components effectively there has to be a methodology that connects the science of psychoacoustics with both electronic and acoustic engineering, and with the art of interesting sound. This presentation looks at how we can use relatively simple psychoacoustic ideas to guide the design process and minimise potential errors.

11:00           Coffee and demonstrations

Two demonstration rooms will be available (the Vivien Stewart Room and the Council Room), in which current 3D and planar spatial reproduction systems can be experienced, compared and enjoyed, with a wide variety of content.

11:30           Perceptual organization of mixtures of sounds from different sources

Brian C J Moore, University of Cambridge

Sounds reaching our ears arrive from many different sources. Our hearing acts as a frequency analyser, separating components in a complex sound mixture. The brain assigns sources to these components. How do we do it?

12:30           Lunch in the Dome and demonstrations

14:00           Basic psychoacoustics for surround recording

Francis Rumsey, University of Surrey

A review of the current state of the art in spatial audio, including both surround and binaural recording and reproduction.

14:45           Recording and reproduction of surround and 3D audio

Arnaud Laborie, Trinnov Audio

This presentation reviews both objective and subjectiveaspects of the latest developments in the acquisition and reproduction of surround and 3D audio, including high spatial resolution microphones, adaptation of the sound to the environment, loudspeaker/room equalisation and image remapping.

15:15           Tea and demonstrations

16:15           Multiple stereo miking techniques in the creation and delivery of immersive surround music

Mark Waldrep, AIX Records

AIX Records' award-winning surround recordings rely extensively on the use of multiple ORTF stereo pairs placed near the performers, combined with an acoustically rich recording environment. This approach allows the listener to be brought into the circle of instrumentalists in a live performance - or listen from the audience.

16:45           Recording the pure space

Crac Downes, Nimbus Records

Nimbus Records has been recording live musical performances in surround for almost 40 years, using a special single-point microphone array. From vinyl to CD and now high-resolution DVD releases, their technique employs a soundfield capture approach that is virtually unique in the commercial recording world.

17:15           Panel Session: What do we really want from surround?

Mark Waldrep, AIX; Adrian Farmer, Nimbus; J Robert Stuart, Meridian Audio Ltd; Francis Rumsey, University of Surrey. Moderator: Richard Elen, Meridian Audio Ltd

Do we want to bring the concert hall to the living room or transport the listener at home to the best seat in the house? Should you place the listener on stage with the musicians or just keep the rear stage for ambience? What happens when there's a picture? These and other questions about practical aspects of working in surround will be addressed.

19:00           Dinner in the Dome (demonstrations continue after dinner)

Thursday 12th April 2007

09:00 to 17:45

09:00           The application of psychoacoustics to small loudspeaker configurations

Ronald Aarts, Philips Research

The requirements for a good sound reproduction system generally conflict with those of consumer products as regards both size and price. A possible solution lies in enhancing listener perception and reproduction of sound by exploiting a combination of psychoacoustics, loudspeaker configurations and digital signal processing.

09:30           Room acoustics for multichannel listening: early reflection control

Bob Walker, Wave Science Technology

One of the main problems in surround listening room design is the destructive effect of early reflections on imaging precision. This paper discusses how to control them acoustically.

10:00           Measuring impulse responses containing complete spatial information

Angelo Farina, University of Parma

Modern digital reverberation systems allow the ambient 'sound' of a natural environment to be used in the studio. To capture these environments in the first place, however, requires a fascinating combination of psychoacoustic research and spherical harmonics.

10:30           Psychoacoustics in sound reinforcement and PA system design

Peter Mapp, Peter Mapp + Associates

Modern sound reinforcement systems make extensive use of psychoacoustic effects, as this paper describes. Haas and precedence effects are used to maximise loudness while maintaining localisation. Head Related Transfer Functions (HRTF) are employed and psychoacoustics also impacts the intelligibility of PA systems.

11:00           Coffee and demonstrations

11:30           Hollywood sound for Cricklewood money

Jerry Ibbotson, Media Mill

This presentation offers a general overview of audio in the games industry, exploring the audio illusions created and used currently within the field of computer games and the field's unique possibilities and limitations.

12:00           Recent developments in parametric coding of spatial audio

Juergen Herre, Fraunhofer IIS

This paper will review the principles and current status of Spatial Audio Coding schemes - one of the most remarkable recent innovations in low-bitrate audio - and discuss their evolution towards Spatial Audio Object Coding with particular focus on the ongoing ISO/MPEG Audio standardisation activities in this field.

12:30           Surround sound in radio drama

Eero Aro, Radio Theatre of the Finnish Broadcasting Company

The aesthetics of surround sound in radio plays will be discussed, including practical solutions to surround drama production and distribution via radio and the internet.

13:00           Lunch in the Dome and demonstrations

14:30           Wave field synthesis: reality or illusion at your choice

Diemer de Vries, Delft University of Technology

Wave Field Synthesis allows spatial sound reproduction without the usual sweet spot limitations. Using arrays of loudspeakers around the audience area, sound sources and their acoustic environment can be (re)produced with natural properties in time and space. During the presentation, the physical background, technological tools and some interesting applications will be discussed.

15:00           Getting the best surround around

Richard G Elen and Peter Carbines, Pyramedia Productions

Imagine you're using the most advanced surround recording/reproduction system ever devised, but virtually nobody can play it back. How do you enable everyone to hear the results of your labours? One answer is to convert to a format that everybody can already enjoy. But are the inevitable compromises worth it? This presentation describes practical examples of how it can be done.

15:30           The hierarchical view

Peter Craven, Algol Research

In 1992, Michael Gerzon proposed a hierarchical representation of multichannel signals as a means of handling the conversion between formats having differing numbers of speakers, providing a framework for cascaded conversions and in particular requiring that conversion to a higher resolution and back should recover the original signals. This presentation suggests applications of this approach to current formats such as 5.1, 7.1, and with-height layouts.

16:00           Tea and demonstrations

16:30           Quality degradation caused by bandwidth-limiting hierarchical encoding schemes

Yu Jiao, University of Surrey

In order to find optimum trade-offs between high data rate and high perceptual quality in multichannel audio transmission, a hierarchical bandwidth limitation algorithm was proposed by the authors. In this presentation, subjective effects of bandwidth limitation based on two hierarchical transform techniques are examined via formal listening tests.

17:00           Illusions of music in space and spaces for music

Bill Martens and Wieslaw Woszczyk, McGill University

Creating illusions of musical instruments positioned in virtual space seems to have been the focus during the early years of spatial sound reproduction, but more knowledge is required for the artistic creation of virtual spaces within which musical sound is to be presented. This paper looks at what has been learned from investigations so far, and explores current research on the auditory spatial imagery associated with virtual acoustic environments.

Disclaimer: The organisers reserve the right to alter the programme without prior notice. Times are approximate. Titles may have been abbreviated in this document, and the outlines provided here may not correspond exactly to the actual papers or presentations.

British Section of the Audio Engineering Society : PO Box 645 : Slough : SL1 8BJ : Tel.01628 663725 : Email