Download Efficient Description and Rendering of Complex Interactive Acoustic Scenes Interactive environmental audio spatialization technology has become commonplace in personal computers and is migrating into portable entertainment platforms (including cell phones) and multiplayer game servers (virtual online worlds). While the primary current application of this technology is 3D game sound track rendering, it is ultimately necessary in the implementation of any personal or shared immersive virtual world (“virtual reality”). The successful development and deployment of such applications in new mobile or online platforms involves maximizing the plausibility of the synthetic 3D audio scene while minimizing the computational and memory footprint of the audio rendering engine. It also requires a flexible, standardized scene description model to facilate the development of applications targeting multiple platforms. This paper reviews a computationally efficient 3-D positional audio and spatial reverberation processing architecture for real-time virtual acoustics over headphones or loudspeakers, compatible with current interactive audio standards (including MPEG-4, OpenAL, JSR 234 and OpenSL ES).
Download Exploring the Sound of Chaotic Oscillators via Parameter Spaces Chaotic oscillators are exciting sources for sound production due to their simplicity in implementation combined with their rich sonic output. However, the richness comes with difficulty of control, which is paramount to both their detailed understanding and in live musical performance. In this paper, we propose perceptually motivated parameter planes as a framework for studying the behavior of chaotic oscillators for musical use. Motivated by analysis via winding numbers, we extend traditional study of chaotic oscillators by using local features that are perceptually inspired. We illustrate the framework on the example of variations of the circle map. However, the framework is applicable for a wide range of sound synthesis algorithms with nontrivial parametric mappings.
Download Performance Portability for Room Acoustics Simulations Numerical modelling of the 3-D wave equation can result in very accurate virtual auralisation, at the expense of computational cost. Implementations targeting modern highly-parallel processors such as NVIDIA GPUs (Graphics Processing Units) are known to be very effective, but are tied to the specific hardware for which they are developed. In this paper, we investigate extending the portability of these models to a wider range of architectures without the loss of performance. We show that, through development of portable frameworks, we can achieve acoustic simulation software that can target other devices in addition to NVIDIA GPUs, such as AMD GPUs, Intel Xeon Phi many-core CPUs and traditional Intel multi-core CPUs. The memory bandwidth offered by each architecture is key to achievable performance, and as such we observe high performance on AMD as well as NVIDIA GPUs (where high performance is achievable even on consumer-class variants despite their lower floating point capability), whilst retaining portability to the other less-performant architectures.
Download FX8010 - A DSP Chip Architecture for Audio Effects FX8010 is a DSP chip architecture specifically designed for time-domain 3D audio and effects processing. It is a 32-channel, 32-bit integer design that can deliver 100MIPS at a 50KHZ audio sample rate. It features powerful delay memory and I/O engines that execute in parallel with and are decoupled from microprogram execution. Its highly regular architecture supports the simultaneous execution of large numbers of separately compiled and downloaded programs with zero-overhead signal patching. A compiler for FX8010 programs generates code from C-style expressions and control-flow constructs. FX8010 has been implemented in two different ASICs for PC multimedia and professional audio applications.
Download Practical Implementation of the 3D Tetrahedral TLM Method and Visualization of Room Acoustics This paper concerns the implementation of a 3D transmission line matrix (TLM) algorithm based on a tetrahedral mesh structure and visualization of room acoustics simulation. Although a well known method, TLM algorithms implemented in 3D are less commonly found in the literature. We have implemented the TLM method using a tetrahedral mesh of pressure nodes with transmission lines lying superimposed on nearest neighbour bonds of a tetrahedral atomic lattice. Results of simulations are compared with those of a standard 3D cartesian mesh and a 2D mesh implementation of TLM. An important feature is a useful graphics interface designed for user-friendly control of room acoustics simulation and visualization in arbitrary shaped rooms containing objects of arbitrary size and number. The paper includes brief discussions of results of using different techniques for modeling totally absorptive or partially absorptive boundaries.
Download Sound-System Design for a Professional Full-Flight Simulator In this paper, we present a sound system to be integrated in an accredited realistic full-flight simulator, used for the training of airline pilots. We discuss the design and implementation of a corresponding real-time signal-processing software providing threedimensional audio reproduction of the acoustic events on a flight deck. Here, the emphasis is on an aircraft of a specific type. We address issues of suitable data acquisition methods, and, most importantly, of functional signal analysis and synthesis techniques.
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 User-Guided Variable-Rate Time-Stretching Via Stiffness Control User control over variable-rate time-stretching typically requires direct, manual adjustment of the time-dependent stretch rate. For time-stretching with transient preservation, rhythmic warping, rhythmic emphasis modification, or other effects that require additional timing constraints, however, direct manipulation is difficult. For a more user-friendly approach, we present work that allows a user to specify a time-dependent stiffness curve to warp the time axis of a recording, while maintaining other timing constraints, such as a desired overall recording length or musical rhythm quantization (e.g. straight-to-swing), providing a notion of stretchability to sound. To do so, the user-guided stiffness curve and timing constraints are translated into the desired time-dependent stretch rate via a constrained optimization program motivated by a physical spring system. Once the time-dependent stretch rate is computed, appropriately modified variable-rate time-stretch processors are used to process the sound. Initial results are demonstrated using both a phase-vocoder and pitch-synchronous overlap-add processor.
Download Simulations of Nonlinear Plate Dynamics: An Accurate and Efficient Modal Algorithm This paper presents simulations of nonlinear plate vibrations in relation to sound synthesis of gongs and cymbals. The von Kármán equations are shown and then solved in terms of the modes of the associated linear system. The modal equations obtained constitute a system of nonlinearly coupled Ordinary Differential Equations which are completely general as long as the modes of the system are known. A simple second-order time-stepping integration scheme yields an explicit resolution algorithm with a natural parallel structure. Examples are provided and the results discussed.
Download Transforming Vibrato Extend in Monophonic Sounds This paper describes research into signal transformation operators allowing to modify the vibrato extent in recorded sound signals. A number of operators are proposed that deal with the problem taking into account different levels of complexity. The experimental validation shows that the operators are effective in removing existing vibrato in real world recordings at least for the idealized case of long notes and with properly segmented vibrato sections. It shows as well that for instruments with significant noise level (flute) independent treatment of noise and harmonic signal components is required.