This text looks at the computer instrument development work and its influence on the composition process. As a preamble to the main discussion, the different types of software for sound generation and transformation are reviewed. The concept of meta-themes is introduced and explored in the context of contemporary music. Two examples of the author’s computer music work are used to discuss the complex relationship between software development and composition. The first piece provides an example of such relationships in the context of ‘tape’ music. The second explores the use of computer instruments in live electroacoustic music. The activities of composition and instrument creation will be shown to be at times indistinguishable and mutually dependent.

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This work presents a novel framework for music synthesis, based on the perceptual structure analysis of pre-existing musical signals, for example taken from a personal MP3 database. We raise the important issue of grounding music analysis on perception, and propose a bottom-up approach to music analysis, as well as modeling, and synthesis. A model of segmentation for polyphonic signals is described, and is qualitatively validated through several artifact-free music resynthesis experiments, e.g., reversing the ordering of sound events (notes), without reversing their waveforms. Then, a compact “timbre” structure analysis, and a method for song description in the form of an “audio DNA” sequence is presented. Finally, we propose novel applications, such as music cross-synthesis, or time-domain audio compression, enabled through simple sound similarity measures, and clustering.

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Although voice has been used as an input modality in various user interfaces, there are no reports of using pitch of the user’s voice for real-time control of computer games. This paper explores pitch-based control for novel games for musical education. Mapping pitch to the position of a game character provides visual feedback that helps you to learn to control your voice and sing in tune. As demonstrated by two example games in this paper, the approach can be applied to both single and two-player games even with just one microphone.

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Digital audio effects are typically implemented on 16 or 24 bit signals sampled at 44.1 kHz. Yet high quality audio is often encoded in a one-bit, highly oversampled format, such as DSD. Processing of a bitstream, and the application of audio effects on a bitstream, requires special care and modification of existing methods. However, it has strong advantages due to the high quality phase information and the elimination of multiple decimators and interpolators in the recording and playback process. We present several methods by which audio effects can be applied directly on a bitstream. We also discuss the modifications that need to be made to existing methods for them to be properly applied to DSD audio. Methods are presented through the use of block diagrams, and results are reported. Keywords: Sigma Delta Modulation, SACD, DSD, Digital Audio Effects, Bitstream Signal Processing

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Drum samples are an important ingredient for many styles of music. Large libraries of drum sounds are readily available. However, their value is limited by the ways in which users can explore them to retrieve sounds. Available organization schemes rely on cumbersome manual classification. In this paper, we present a new approach for automatically structuring and visualizing large sample libraries through audio signal analysis. In particular, we present a hierarchical user interface for efficient exploration and retrieval based on a computational model of similarity and self-organizing maps.

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This paper presents the work on a prototype spatial auditory display. Using high-definition audio rendering a sample application was presented to a mixed group of users with visual disabilities and normal sighted users. The evaluation of the prototype provided insights into how effective spatial presentation of sound can be in terms of human-computer interaction (HCI). It showed that typical applications with the most common interaction tasks like menus, text input and dialogs can be presented very effectively using spatial audio. It also revealed that there is no significant difference in effectiveness between normal sighted and visually impaired users. We believe that spatial auditory displays are capable to provide the visually impaired and blind access to modern information technologies in a more efficient way than common technologies and that they will be inevitable for multimodal displays in future applications.

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We here introduce the opportunity of using visualization of sound as a control interface, for artistic live performance as well as for new digital audio effects developments. Two different approaches are exposed. The first access consists in using video matrixes for mapping the variables parameters of sound processing, with the coordinates of any controller in a 2D plane or 3D space. The second access proposes a visualization of sound that modifies sound data by processing the data of the image itself with its own graphical properties. Exploring this kind of « transducting » relation between visual and audio may be interesting for artistic creation domain using virtual surroundings; it may cause an interest for the real time digital audio, for audiovisual mixing and new interfaces for sound design. Besides, it points the opportunity of developing 3D control interfaces for audio and visual processes.

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