Download Dispersion Modeling in Waveguide Piano Synthesis Using Tunable Allpass Filters This paper extends a previously proposed method for designing filters simulating the dispersion phenomenon occurring in string instruments. In digital waveguide synthesis, the phenomenon is traditionally modeled by inserting an allpass filter to the string model feedback loop. In this paper, the concept of tunable dispersion filter design, which provides a closed-form formula to design a dispersion filter, is applied to a cascade of first-order allpass filters. Moreover, the method is extended to design a filter cascade including an arbitrary number of first-order filters. In addition, it is shown how the designed dispersion filter can be used in a waveguide piano synthesis model.
Download On the Dynamics of the Harpsichord and its Synthesis It is common knowledge that the piano was developed to produce a keyboard instrument with a larger dynamic range and higher sound radiation level than the harpsichord possesses. Also, the harpsichord is a plucked string instrument with a very controlled mechanism to excite the string. For these reasons it is often falsely understood that the harpsichord does not exhibit any dynamic variation. On the contrary, the signal analysis and the listening test made in the this study show that minor but audible differences in the dynamic levels exist. The signal analysis portrays that stronger playing forces produce higher levels in harmonics. The energy given by the player is not only distributed to the plucking mechanism but also carried on from the key to the body. This is evident from the increased level of body mode radiation. A synthesis model for approximating the dynamic behavior of the harpsichord is also proposed. It contains gain and timbre control, and a parallel filter structure to simulate the soundboard knock characteristic for high key velocity tones.
Download An Interdisciplinary Approach to Audio Effect Classification The aim of this paper is to propose an interdisciplinary classification of digital audio effects to facilitate communication and collaborations between DSP programmers, sound engineers, composers, performers and musicologists. After reviewing classifications reflecting technological, technical and perceptual points of view, we introduce a transverse classification to link disciplinespecific classifications into a single network containing various layers of descriptors, ranging from low-level features to high-level features. Simple tools using the interdisciplinary classification are introduced to facilitate the navigation between effects, underlying techniques, perceptual attributes and semantic descriptors. Finally, concluding remarks on implications for teaching purposes and for the development of audio effects user interfaces based on perceptual features rather than technical parameters are presented.
Download A New Paradigm for Sound Design A sound scene can be defined as any “environmental” sound that has a consistent background texture, with one or more potentially recurring foreground events. We describe a data-driven framework for analyzing, transforming, and synthesizing high-quality sound scenes, with flexible control over the components of the synthesized sound. Given one or more sound scenes, we provide well-defined means to: (1) identify points of interest in the sound and extract them into reusable templates, (2) transform sound components independently of the background or other events, (3) continually re-synthesize the background texture in a perceptually convincing manner, and (4) controllably place event templates over the background, varying key parameters such as density, periodicity, relative loudness, and spatial positioning. Contributions include: techniques and paradigms for template selection and extraction, independent sound transformation and flexible re-synthesis; extensions to a wavelet-based background analysis/synthesis; and user interfaces to facilitate the various phases. Given this framework, it is possible to completely transform an existing sound scene, dynamically generate sound scenes of unlimited length, and construct new sound scenes by combining elements from different sound scenes. URL: http://taps.cs.princeton.edu/
Download The Mellin Pizzicator In this paper an application of the Mellin transform to the digital audio effects will be presented. Namely, low-pass and band-pass like filtering in the Mellin domain will be described and used for obtaining some kind of pizzicato effect on audio samples (musical instruments, but not only). The pluck and damp effects will be obtained using filtering in Mellin domain only. The algorithm used for implementing the Mellin (scale) transform has been presented in DAFx’04 [1].
Download Onset Detection Revisited Various methods have been proposed for detecting the onset times of musical notes in audio signals. We examine recent work on onset detection using spectral features such as the magnitude, phase and complex domain representations, and propose improvements to these methods: a weighted phase deviation function and a halfwave rectified complex difference. These new algorithms are compared with several state-of-the-art algorithms from the literature, and these are tested using a standard data set of short excerpts from a range of instruments (1060 onsets), plus a much larger data set of piano music (106054 onsets). Some of the results contradict previously published results and suggest that a similarly high level of performance can be obtained with a magnitude-based (spectral flux), a phase-based (weighted phase deviation) or a complex domain (complex difference) onset detection function.
Download Exact Discrete-Time Realization of a Dolby B Encoding/Decoding Architecture An algebraic technique which computes nonlinear, delay-free digital filter networks is applied to model the Dolby B in the discretetime. The model preserves the topology of the analog system, and imports the characteristics of the nonlinear processing blocks which are responsible of the peculiar functioning of Dolby B. The resulting numerical system exhibits qualitatively similar dynamic behavior and performance – full compliance with the Dolby B specifications would be achieved by deriving, from comprehensive data sheets of the system, accurate discrete-time models of the analog processing blocks. Results demonstrate that the computation converges if proper iterative methods are employed.
Download Circle Maps as a Simple Oscillators for Complex Behavior: II. Experiments The circle map is a general non-linear iterated function that maps the circle onto itself. In its standard form it can be interpreted as a simple sinusoidal oscillator which is perturbed by a non-linear term. By varying the strength of the non-linear contribution a rich array of non-linear responses can be achieved, including waveshaping, pitch-bending, period-doubling and highly irregular patterns. We describe a number of such examples and discuss their subjective auditory perception.
Download Sound Processing in OpenMusic This article introduces some new possibilities of audio manipulations and sound processing in the Computer-Aided Composition environment OpenMusic. Interfaces with underlying sound processing systems are described, with an emphasis on the use of the symbolic and visual programming environment for the design of sound computation processes.
Download Consistency of Timbre Patterns in Expressive Music Performance Musical interpretation is an intricate process due to the interaction of the musician’s gesture and the physical possibilities of the instrument. From a perceptual point of view, these elements induce variations in rhythm, acoustical energy and timbre. This study aims at showing the importance of timbre variations as an important attribute of musical interpretation. For this purpose, a general protocol aiming at emphasizing specific timbre patterns from the analysis of recorded musical sequences is proposed. An example of the results obtained by analyzing clarinet sequences is presented, showing stable timbre variations and their correlations with both rhythm and energy deviations.