Etienne Deleflie’s research while affiliated with University of Wollongong and other places

Ambisonics is a 3D audio surround rendering and representation approach based on spherical harmonics with loud-speaker independent transmission channels. Although it was developed in the seventies and the techniques are well known, there are disagreements how to normalize, store and exchange Ambisonic data. This paper's mission is to propose a standard for the Ambisonics community and it should be seen as an encouragement to use the proposed convention, in order to facilitate exchange and communication. This standard is named ambiX (Ambisonics exchangeable). For the case that mixed order or reduced Ambisonic signal sets are beneficial, the format includes a simple matrix -named "adaptor matrix". This matrix can be freely configured to re-order, complete, re-normalize, or embed the transmitted or stored audio channels to a default set of periphonic Ambisonic signals. It is advocated as extended format, because it enables new techniques to reduce the Ambisonic signal set utilizing prior knowledge about restricted surround geometries like hemispherical or circular. Providing a default periphonic decoder for all surround geometries ensures universal applicability, while inspection tools for the adaptor matrix are advanced means for optimal decoding. IEM provides a small "proof of concept" implementation of tools to write, read audio data and the adaptor matrix, as well tools to analyze the adaptor matrix graphically to select the best decoder for given files.

This paper discusses a new approach to computer music synthesis where music is composed specifically for performance using mobile handheld devices. Open source cross-platform computer music synthesis software initially developed for composing on desktop computers has been used to program a Linux phone. Work presented here allows mobile devices to draw on these resources and makes comparisons between the strengths of each program in a mobile phone environment. Motivation is driven by aspirations of the first author who seeks to further develop creative mobile music performance applications first developed in the 1980s using purpose-built hardware and later, using j2me phones. The paper will focus on two different musical implementations of his microtonal composition entitled Butterfly Dekany which was initially implemented in Csound and later programmed using Pure Data. Each implementation represents one of the two programming paradigms that have dominated computer music composition for desktop computers namely, music synthesis using scripting and GUI-based music synthesis. Implementation of the same work using two different open source languages offers a way to understand different approaches to composition as well providing a point of reference for evaluating the performance of mobile hardware. KeywordsLinux-mobilephone-csound-pure data-chuck-synthesis toolkit

Granular synthesis techniques have been appropriated for 3D sound spatialisation in a number of ways, such as the spatial encoding of individual grains. This paper proposes a new technique that aims to use the spatial information already encoded in ambisonic signals, the principle hypothesis being that this encoding is actually retained at the granular level. This opens up exciting new possibilities for spatial sound. The paper outlines some of these possibilities but focuses primarily on the synthesis of non-point sources of sound which forms the basis for a second hypothesis, involving functions that relocate spatially encoded grains in time.

The tools for spatial composition typically model just a small subset of the spatial audio cues known to researchers. As composers explore this medium it has become evident that the nature of spatial sound perception is complex. Yet interfaces for spatial composition are often simplistic and the end results can be disappointing. This paper presents an interface that is designed to liberate the composer from thinking of spatialised sound as points in space. Instead, visual images are used to define sound in terms of shape, size and location. Images can be sequenced into video, thereby creating rich and complex temporal soundscapes. The interface offers both the ability to craft soundscapes and also compose their evolution in time.