Download An Extension for Source Separation Techniques Avoiding Beats
The problem of separating individual sound sources from a mixture of these, known as Source Separation or Computational Auditory Scene Analysis (CASA), has become popular in the recent decades. A number of methods have emerged from the study of this problem, some of which perform very well for certain types of audio sources, e.g. speech. For separation of instruments in music, there are several shortcomings. In general when instruments play together they are not independent of each other. More specifically the time-frequency distributions of the different sources will overlap. Harmonic instruments in particular have high probability of overlapping partials. If these overlapping partials are not separated properly, the separated signals will have a different sensation of roughness, and the separation quality degrades. In this paper we present a method to separate overlapping partials in stereo signals. This method looks at the shapes of partial envelopes, and uses minimization of the difference between such shapes in order to demix overlapping partials. The method can be applied to enhance existing methods for source separation, e.g. blind source separation techniques, model based techniques, and spatial separation techniques. We also discuss other simpler methods that can work with mono signals.
Download Inharmonic Sound Spectral Modeling by Means of Fractal Additive Synthesis
In previous editions of the DAFX [1, 2] we presented a method for the analysis and the resynthesis of voiced sounds, i.e., of sounds with well defined pitch and harmonic-peak spectra. In a following paper [3] we called the method Fractal Additive Synthesis (FAS). The main point of the FAS is to provide two different models for representing the deterministic and the stochastic components of voiced-sounds, respectively. This allows one to represent and reproduce voiced-sounds without loosing the noisy components and stochastic elements present in real-life sounds. These components are important in order to perceive a synthetic sound as a natural one. The topic of this paper is the extension of the technique to inharmonic sounds. We can apply the method to sounds produced by percussion instruments as gongs, tympani or tubular bells, as well as to sounds with expanded quasi-harmonic spectrum as piano sounds.