Download Sonification of the Fission Model as an Event Generation System I am proposing an event generation system for sonification purposes, where a simplified chain reaction model known as nuclear fission in physics is used. The basic background of the fission model, mapping of parameters as sonic entities and technical aspects of the realization procedure are presented.
Download Memory Reduction Technique of Spreading Function in MPEG AAC Encoder In order to reduce the computational complexity of an MPEG AAC encoder, calculation of spreading function, which is the critical algorithm in the psychoacoustic model, can be replaced with look-up tables. However, the memory size of the table is considerably large in DSP or hardware implementation for portable devices. The paper deals with the methods to reduce the memory size. We modified a method originally used in an MP3 software encoder and adopted it in an MPEG AAC encoder. The result shows that only about one-third of the original size is required in programmable processor implementation such as DSP. Moreover, for hardware implementation, we analyzed the wordlength and reduced the size to only 3.6% compared to that for a 16-bit DSP while maintaining audio quality.
Download An MDCT-Based Psychoacoustic Model Co-Processor Design for MPEG-2/4 AAC Audio Encoder The Psychoacoustic Model (PAM) is a very important role in MPEG-2/4 Advanced Audio Coding (AAC) encoding. It determines sound quality of a given encoder and influences a lot in computational complexity. This paper presents a new architecture design for MDCT-based PAM co-processor. This work is based on the dedicated hardware design which is different from traditional programmable approaches. Moreover, to reduce the complexity, we replace the calculations of spreading function with reduced fixed coefficients, and decrease the transform kernels from three to one unit.
Download Synthesis by Mathematical Models Sound synthesis methods can be interpreted, from a mathe matical point of view, as a collection of techniques of selecting and conceptually organizing elements of a Hilbert space. In this sense, mathematics, being a highly structured and sophisticated system of classification, modeling and categorization, seems to be the natural tool to describe existing synthesis methods and to pro pose new ones. Because, from this perspective, one can think of any available (or theoretically predictable, or imaginable) synthe sis method as a collection of procedures to deal with meaningful parameters, with the term ”synthesis by mathematical models” we mean an extensive use of the modeling and categorization power of mathematics applied to the world of sounds. In this paper we give a few examples of sound synthesis tech niques, based on mathematical models. After reviewing shortly FM synthesis and synthesis by nonlinear distortion, and suggest ing some, to our advice, interesting open problems, we propose two different new methods: synthesis by means of elliptic func tions and synthesis by means of nowhere (or almostnowhere) dif ferentiable functions and lacunary series. The resulting waveforms have been produced using CSound as an audio engine, driven by Python scripts.
Download Sound Texture Modeling and Time-Frequency LPC This paper presents a method to model and synthesize the textures of sounds such as fire, footsteps and typewriters using time and frequency domain linear prediction coding (TFLPC). The common character of this class of sounds is that they have a background “din” and a foreground transient sequence. By using LPC filters in both the time and frequency domain and a statistical representation of the transient sequence, the perceptual quality of the sound textures can be largely preserved, and the model used to manipulate and extend the sounds.
Download Making Sound with Numbers, Six Years Later In the first edition of the DAFx Conferences an extensive tutorial on professional and research software devoted to sound and music making was presented. The present paper attempts a revision of the concepts expressed in that tutorial, focusing particularly to the aspects related to research and innovation fostered by a strong paradigm shift that has happened in the mean time: that of Free Software development. Of course, this paradigm shift has also had its difficulties and harsh spots, requiring many extra efforts in order to overcome them. This paper will try to describe these as well as to outline the current state-of-the-art in the field.
Download Computer Instrument Development and the Composition Process 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.
Download Event-Synchronous Music Synthesis 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.
Download Musical Computer Games Played by Singing 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.
Download Digital Audio Effects Applied Directly on a DSD Bitstream 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