Download Extracting More Detail from the Spectrum with Phase Distortion Analysis
In the sinusoidal analysis of sound, using the Short Time Fourier Transform (STFT), there is the assumption that the signal is locally stationary within each FFT frame. If, as in practice, this assumption is violated, the spectrum becomes distorted. Phase Distortion Analysis (PDA) was introduced in 1995 [1] to enhance the analysis of degraded peaks, by using the distortion itself as a source of information about the signal nonstationarity. It was shown that the first order frequency and amplitude modulation could be measured from the degree of phase shift close to the maximum of the mainlobe peak. This paper presents advances with the PDA technique, in particular a neural network implementation that makes estimation robust to noise. The capability to analyse nonstationarities relaxes the restraint on keeping the FFT analysis window short and therefore effectively improves time-frequency resolution. This, in turn, promises greater analysis-synthesis quality through improved identification and tracking of partials during the analysis phase.
Download Musical Gestures and Audio Effects Processing
We introduce the notion of musical gestures as time varying measurements which identify the audio input stream’s musical skeleton without attempting to implement any involved model of musical understanding. Living comfortably at an intermediate level of abstraction between wave forms and music transcriptions, these musical gestures are used to control the behavior of an audio processing module. The resulting scheme qualifies as an audio effects processing system as it essentially transforms an audio stream into another.
Download Reproducing 3D-Sound for Videoconferencing: a comparison between Holophony and Ambisonic
Current research in videoconferencing is focussed on 3D-Sound reproduction over a wide listening area. This paper compares two methods: Holophony and Ambisonic. First, it will be shown that Ambisonic actually corresponds to a particular case of holophonic reconstruction, then the specificities of the two approaches will be analysed in terms of complexity and size of listening area. As a result, a third method, which shall combine the advantages of both Holophony and Ambisonic, will be suggested.
Download Constraint-Based Spatialization
This paper describes an application of constraint programming to interfaces for audio mixing. MidiSpace is an interface representing each sound source of a musical piece as a graphical icon, as well as an object corresponding to the listener in a window. MidiSpace is coupled to a spatialization system so that moving graphical objects modifies the audio mixing of the musical piece according to the respective position of the sound sources to the avatar. We further introduce a constraint-based mechanism which allows to maintain consistency in the overall mixing. Constraints represent properties of related sound sources, which should always remain true, and may be stated by the user through the interface. When an object is moved, a constraint solver uses the constraints to propagate changes. We describe the library of currently designed constraints, and propose an extension of the system to handle reproduction systems with multiple loudspeakers.
Download Signal Characterization in terms of Sinusoidal and Non-Sinusoidal Components
This paper addresses the problem of signal characterization in terms of sinusoidal and non-sinusoidal com-ponents. A first measure of sinusoidality is reviewed. Drawbacks of this sinusoidal estimator are investigated and solutions proposed. Estimation of sinusoidality on non-stationary signal is then made on apre-processed signal. A phase derived sinusoidality measure and the use of Re-estimated Spectra are introduced which allow deriving very precise and local characteristics. Finally, this characterization is used in anew synthesis scheme using Additive and PSOLA synthesis.
Download Virtual Sound Source Positioning and Mixing in 5.1. Implementation on the Real-Time System Genesis
The aim of this article is to compare two multi-speaker spatialization techniques - Vector Base Panning (VBP) and Ambisonics - on a particular loudspeaker layout. Theory is presented for configurations in the horizontal plane. A way to deal with the elevation effect for such layouts is proposed. A new "local" panning method is introduced. VBP and Ambisonics are compared on a 5.1 configuration by means of objective simulation and preliminary listening tests on the real-time DSP system Genesis. This study could find recording and mixing applications in home cinema and multimedia.
Download Digital Signal Processing Techniques for Non-exponentially Decaying Reverberation
In this paper we show several digital signal processing techniques that can be used for non-exponentially decaying artificial reverberation. Traditional recursive filter techniques used for simulating the diffuse part of reverberation produce an exponentially decaying reverberation. We show how traditional reverberation algorithms can be modified and combined to create non-exponentially decaying reverberation. The techniques presented here can be used for interesting musical effects and speech enhancement. As an application example, a real-time system using the Motorola DSP56002 digital signal processor is presented.
Download Dynamical spatialisation of sounds. HOLOPHON: a graphical and algorithmical editor for S1
This document describes a new sound spatialisation tool running on the Macintosh ProTools TDM platform. This tool allows the user to program the movements of multiple sound files through a multi-speakers sound diffusion system. It is composed of two pieces of software, Σ1 from APBTOOLS, used for calculating movement, and Holophon from GMEM, used for an algorithmic or graphical programming of these movements.
Download SMS Composer and SMS Conductor: Applications for Spectral Modeling Synthesis Composition and Performance
SMS Composer and SMS Conductor are Windows applications designed to take musical advantage of both the flexibility and potential of SMS sound transformations and its current capability for real-time synthesis. SMS Composer offers a powerful compositional environment for SMS score generation, editing and synthesis. SMS Conductor is a real-time SMS controller, mainly focused on the problem of tracking and translating conductors’ queues into time-stretch synthesis fluctuations.
Download A Proposal for using SMS for Expression Modeling
Spectral models have proven to be a successful method for analyzing and re-synthesizing natural and acoustic sounds, to the extent that a musical phrase can also be modeled in order to extract performance parameters. This paper suggests various parameters which are embedded in the spectral analysis or .sms file and proposes some methods which can be used for expression modeling based upon compositional, perceptive, and cognition approaches. The focus is on achieving the means to construct a translation algorithm which the composer can use as a tool to analyze expressive material such as a musical phrase or a spoken sentence of text, and apply detected parameters to the vectors of a physical model or a synthesis algorithm..