Download TAPIIR, A Software Multitap
The use of delays is one of the oldest techniques for effects processing and electro-acoustic composition. Originally, tape-loops were used to create effects of echo and reverb. Nowadays, most hardware effect processors provide digital implementations. These have a clearly superior soundquality compared to tape-delays, but also imply some restrictions. Delay-length is limited by the internal memory, and delay time accuracy is often sacrificed for computational efficiency or even deliberately restricted for user-interfacing. This paper presents a dedicated software implementation of a flexible multi-delay, that aims to combine flexibility and high accuracy with high quality audio and usability. At the same time, several important issues in software effect processing will be addressed.
Download Time-Varying Filter In Non-Uniform Block Convolution
This paper will describe further research on a real-time convolution algorithm for long a FIR filter based on nonuniform bock partitioning. The static behaviour of the algorithm which solves the dilemma between the computational load and the latency of the processing operation is well examined in literature. New directions are investigated to exploit the inherent features of the algorithm and utilise them for audio applications. Especially a dynamic exchange of filter coefficients or subsets of them of a room impulse response is discussed and implemented. Unlike to traditional DSP solutions the prototype is realised in portable software objects and components that can be compiled on multi-propose processing units like off-the-shelf computers with standard audio facilities and different operating systems. Keywords : convolution, spatial sound processing, real-time, room acoustics, sonification
Download Sound Morphing With Gaussian Mixture Models
In this work a sound transformation model based on Gaussian Mixture Models is introduced and evaluated for audio morphing. To this aim, the GMM is used to build the acoustic model of the source sound, and a set of conversion functions, which rely on the acoustic model, is used to transform the source sound. The method is experimented on a set of monophonic sounds and results show that it provides promising features.
Download Voice source analysis for pitch-scale modification of speech signals
Much research has shown that the voice source has strong influence on the quality of speech processing . But in most of the existing speech modification algorithms, the effect of the voice source variation is neglected. This work explains why the existing modification scheme can’t truly reflect the voice source variation during pitch modification. We use synthesized voiced speech sound to compare an existing pitch modification scheme with our proposed voice source scaling based modification scheme. Results show that voice source scaling based pitch modification can be used for wider range pitch modification. Key word: speech pitch modification, voice source, formant synthesis.
Download Multiresolution Sinusoidal/Stochastic Model For Voiced-Sounds
The goal of this paper is to introduce a complete analysis/resynthesis method for the stationary part of voiced-sounds. The method is based on a new class of wavelets, the Harmonic-Band Wavelets (HBWT). Wavelets have been widely employed in signal processing [1, 2]. In the context of sound processing they provided very interesting results in their first harmonic version: the Pitch Synchronous Wavelets Transform (PSWT) . We introduced the Harmonic-Band Wavelets in a previous edition of the DAFx . The HBWT, with respect to the PSWT allows one to manipulate the analysis coefficients of each harmonic independently. Furthermore one is able to group the analysis coefficients according to a finer subdivision of the spectrum of each harmonic, due to the multiresolution analysis of the wavelets. This allows one to separate the deterministic components of voiced sounds, corresponding to the harmonic peaks, from the noisy/stochastic components. A first result was the development of a parametric representation of the HBWT analysis coefficients corresponding to the stochastic components [5, 7]. In this paper we present the results concerning a parametric representation of the HBWT analysis coefficients of the deterministic components. The method recalls the sinusoidal models, where one models time-varying amplitudes and time varying phases [8, 9]. This method provides a new interesting technique for sound synthesis and sound processing, integrating a parametric representation of both the deterministic and the stochastic components of sounds. At the same time it can be seen as a tool for a parametric representation of sound and data compression.
Download Influence Of Frequency Distribution On Intensity Fluctuations Of Noise
This article introduces mathematical parameters that generalize the frequency distribution of the statistical and spectral model. We show experiments that determine the influence of these parameters on the intensity fluctuations of the synthesized noise, accordingly to the theory developed by psycho-acoustic works. The main goal of these experiments is to be able to analyse and synthesize bands of noise with different spectral densities.
Download Scalable Spectral Reflections In Conic Sections
The object of this project is to present a novel digital audio effect based on a real-time, windowed block-based FFT and inverse FFT. The effect is achieved by mirroring the spectrum, producing a sound effect ranging from a purer rendition of the original, through a rougher one, to a sound unrecognisable from the original. A mirror taking the shape of a conic section is constructed between certain partials, and the modified spectrum is created by reflecting the original spectrum in this mirror. The user can select the type and continuously vary the amount of curvature, typically ‘roughening’ the input sound quite gratifyingly. We demonstrate the system with live real-time audio via microphone.
Download Phase Vocoder Applications In Grm Tools Environment
This paper focuses on four real time audio processes based on the phase-vocoder, or more generally on analysis/synthesis algorithms by Fourier transformation. These effects are available as VST (Steinberg) or RTAS (Digidesign) plugins. Constraints dependent on an exclusive real-time use will be exposed as well as the related issues on algorithmics and user interface.
Download Extending Digital Waveguides To Include Material Modelling
Digital Waveguides have been extensively used for musical instrument and room acoustics modelling. They can be used to form simplistic models for ideal wave propagation in one, two and three dimensions. Models in 1D for string and wind instrument synthesis and more recently a model for a drum, realised by interfacing 2D and 3D waveguide meshes, have been presented . A framework is thus in place for the virtual construction of new or abstract musical instruments. However, straight-forward waveguides and waveguide meshes behave in an extremely indeal nature and phenomena such as stiffness and internal friction are often compromised or ignored altogether. In this paper we discuss and evaluate models which incorporate material parameters. We review a 1D bar model, and then present a 2D extension to model plates. We also discuss the problem of modelling frequency dependent damping, by describing a waveguide model of a visco-elastically damped string.