Download Statistical approach for sounds modeling This article introduces a mathematical approach to extracting some statistical parameters from noise-like sounds. This approach could define a new spectral model or extend existing ones to analyze and synthesize such complex sounds. In the future, this method could also permit electro-acoustic composers to make musical transformations. We have performed several synthesis tests with synthetic and natural sounds using these parameters. The main assumptions is that analyzed sounds must not contain any transient or slow-varying deterministic component. The natural sounds resynthesized during our experiments sounds like the original ones even if some defects are perceptible because of the analysis limitations. We propose some initial solutions for future works.
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 Adapting the Overlap-Add Method to the Synthesis of Noise Spectral synthesis techniques often use the OverLap-Add method. But in the case of noise synthesis, both experiments and theory show that this method introduces intensity fluctuations which imply audible artifacts. We propose here new methods to avoid these variations. The first one consists in multiplying the resulting signal by another weighting window to compensate dynamic fluctuations. The second one defines a new OLA weighting window. The third one concerns only noises synthesized with sinusoidal components and uses time-shifting to cancel artifacts.
Download Real-Time Noise Synthesis with Control of the Spectral Density We propose in this paper a spectral synthesis model to generate noisy sounds with independent control parameters for spectral density and spectral envelope. Algorithms defining in a efficient way these spectral properties from the statistical parameters of the model are presented in details. Real-time implementation is composed of many methods which can be sequenced.
Download A New Analysis Method for Sinusoids+Noise Spectral Models Existing deterministic+stochastic spectral models assume that the sounds are with low noise levels. The stochastic part of the sound is generally estimated by subtraction of the deterministic part: It is assumed to be the residual. Inevitable errors in the estimation of the parameters of the deterministic part result in errors – often worse – in the estimation of the stochastic part. We propose a new method that avoids these errors. Our method analyzes the stochastic part without any prior knowledge of the deterministic part. It relies on the study of the distribution of the amplitude values in successive short-time spectra. Computations of the statistical moments or the maximum likelihood lead to an estimation of the noise power density. Experimentations on synthetic or natural sounds show that this method is promising.