Timbre from Sound Synthesis and High-level Control Perspectives

International audienceExploring the many surprising facets of timbre through sound manipulations has been a common practice among composers and instrument makers of all times. The digital era radically changed the approach to sounds thanks to the unlimited possibilities offered by computers that made it possible to investigate sounds without physical constraints. In this chapter we describe investigations on timbre based on the analysis by synthesis approach that consists in using digital synthesis algorithms to reproduce sounds and further modify the parameters of the algorithms to investigate their perceptual relevance. In the first part of the chapter timbre is investigated in a musical context. An examination of the sound quality of different wood species for xylophone making is first presented. Then the influence of instrumental control on timbre is described in the case of clarinet and cello performances. In the second part of the chapter, we mainly focus on the identification of sound morphologies, so called invariant sound structures responsible for the evocations induced by environmental sounds by relating basic signal descriptors and timbre descriptors to evocations in the case of car door noises, motor noises, solid objects, and their interactions

Retrieving and Recreating Musical Form

Abstract. This paper discusses musical form from a cognitive and a computational viewpoint. While several time-windows exist in the brain, we here put emphasis on the superchunks of up to more than 30 seconds lengths. We compare a strategy for auditive analysis based on human cognition with a strategy for automatic analysis based on feature extraction. The feature extraction is based on the musical features rhythm, timbre and chroma. We then consider the possible consequences of this approach for the development of music generating software

Real-Time Perceptual Simulation of Moving Sources: Application to the Leslie Cabinet and 3D Sound Immersion

Perception of moving sound sources obeys different brain processes from those mediating the localization of static sound events. In view of these specificities, a preprocessing model was designed, based on the main perceptual cues involved in the auditory perception of moving sound sources, such as the intensity, timbre, reverberation, and frequency shift processes. This model is the first step toward a more general moving sound source system, including a system of spatialization. Two applications of this model are presented: the simulation of a system involving rotating sources, the Leslie Cabinet and a 3D sound immersion installation based on the sonification of cosmic particles, the Cosmophone

Lutherie informatique et lutherie acoustique

This paper presents some applications of time-frequency representations to the study of guitar sounds. These techniques allow to estimate acoustically relevant parameters such as frequency and time behaviours of the components. From real guitar sounds recorded in an anechoïc room, we have made a link between the structure modifications of the instrument and sound parameters such as Helmholtz, top-plate and the first harmonic components of the sound. In addition, these techniques allow to re-synthesize independantly each component, giving a new audio-tool to the instrument designer

TRAITEMENT DES SIGNAUX ACOUSTIQUES ASYMPTOTIQUES PAR REPRÉSENTATION TEMPS-ÉCHELLE

Time Scale Representation display the energy of analytic signals as a function of time and dilation ratio. These representation are derived using the covarlance properties for time scaling and delay. Asymptotic signals may be easily interpreted when transformed by frequency transformation related to time parity. Acoustic effects related to various media are represented by such transformations.La Représentation Temps Echelle distribue l'énergie des signaux dans le plan des dates et des taux d'hémothétie. Elle utilise la covarlance par changement d'échelle. Dans le cas des signaux asymptotlques la transformation fréquentielle équivalente à la parité possède une Interprétation commode vu certains effets acoustiques observés dans le canal sous marin

Design and perceptual evaluation of a fully immersive three-dimensional sound spatialization system

International audienceThis article presents the design, the implementation, and the perceptual evaluation of a multichannel loudspeaker array for the creation of 3D virtual sound environments. Dedicated to perceptual and postural studies, this system consists of 42 loudspeakers equally distributed around the listener on a full sphere (3 meter diameter), allowing to synthetize sounds moving within the whole 3D space. The spatial distribution of the loudspeakers makes it possible to use two different 3D rendering approaches: a physical approach through the use of 3D Higher Order Ambisonics (HOA) method up to fifth order and a perceptual approach through the use of Vector-Based Amplitude Panning (VBAP) method. A localization experiment was carried out in order to investigate the performance of the present system in terms of localization accuracy. Furthermore, this experiment aimed to explore the perceptual impact of the rendering methods (e.g. HOA and VBAP), and to evaluate the improvement of localization performance with respect to the ambisonic order (from third to fifth order). Differences between rendering methods are investigated in terms of azimuth and elevation localization errors, and front-back and up-down confusions. Finally, virtual sound source localization is compared to real sound source localization generated by 42 loudspeakers