Synthesis of breathy vowels: some research methods.

Abstract. When vowels are synthesised by means of a source-filter model, a delta-pulse train is often used as a source signal. Although breathiness can to some extent be simulated by using a sophisticated glottal-source model, a more natural simulation of breathiness requires the addition of aspiration noise. When stationary noise is used, however, the noise is to a large extent perceived as coming from a separate sound source which hardly contributes to the breathy timbre of the vowel. This problem can be solved by using noise with a temporal envelope of the same periodicity as the pulse train. In a simple source-filter model, a combination of lowpass-filtered pulses and synchronous highpass-filtered noise bursts of equal energy was used as a source signal. In this way, the noise was no longer perceived as a separate sound, but integrated perceptually with the strictly periodic part of the signal. It will be shown that this integration consists of both a reduction of the loudness of the separate noise stream and a timbre change in the breathy vowel. Zusammenfassung. Bei der Synthese von Vokalen mit einem Quellen-Filtermodell wird als Quellensigna[ oft eine Deltapulsfolge verwendet. Obwohl eine hauchige Stimme bis zu einem gewissen Grad mit einem verfeinerten Glottal-Quellenmodell simuliert werden kann, erfordert eine natiirlich klingende Simulation doch die Addition yon Rauschen. Wenn zu diesem Zweck allerdings station~ires Rauschen verwendet wird, wird dieses meist als yon einer getrennten Signalquelle stammend wahrgenommen und tr~gt damit kaum zum Eindruck eines gehauchten Vokals bei. Dieses Problem kann dadurch gelOst werden, dab das Rauschen mit einer zeitlichen Einhiillenden versehen wird, deren Periodizit~it dieselbe ist wie die der Pulsfolge. In einem einfachen Quellen-Filtermodell wurde eine Kombination yon tiefpaBgefilterten Pulsen und synchronen hochpal~gefilterten Rauschpulsen mit dergleichen Energie als Quellensignal verwendet. Dadurch wurde das Rauschen nicht mehr als getrenntes Signal wahrgenommen, sondern perzeptiv mit dem periodischen Signalanteil integriert. In dem Beitrag wird gezeigt, dab diese Verschmelzung einerseits auf einer Verringerung der Lautheit des Rauschsignals und andererseits auf einer Klangfarben~inderung im gehauchten Vokal beruht. R6sum6. La synth6se de voyelles au moyen d'un mod61e source-filtre s'effectue souvent avec un train d'impulsions delta comme signal d'entr6e. Bien que des modules sophistiqu6s de la source glottale puissent ~tre employ6s, dans une certaine mesure, afin de simuler une voix souffi6e, une simulation plus naturelle exige l'addition d'un bruit d'aspiration. Cependant, lorsqu'un bruit stationnaire est employ6, il sera per~u en bonne partie comme provenant d'une source sonore s6par6e qui ne contribue pas au timbre souffi6 de la voyelle. Ce probl6me peut 6tre r6solu en utilisant un bruit ayant une enveloppe temporelle de la m6me p6riodicit6 que le train d'impulsions. Dans un simple mod61e source-filtre, des impulsions filtr6es passe-bas combin6es ~ un bruit pulsatif synchrone filtr6 passe-haut ~ 6nergie 6galis6e ont 6t6 employ6es comme signal de source. De cette fa~on, le bruit n'est plus per~u s6par6ment, mais est int6gr6 perceptuellement ~t la partie strietement p6riodique du signal. II sera d6montr6 que cette int6gration consiste ~ la lois en une r6duction de la force sonore du bruit et en une alt6ration du timbre de la voyelle souffi6e

Auditory cues determining the perception of the size and speed of rolling balls

Presented at the 7th International Conference on Auditory Display (ICAD), Espoo, Finland, July 29-August 1, 2001.This study investigates the auditory perception of the size and the speed of rolling balls. Prior experiments showed that subjects can discriminate differences in size and speed of wooden rolling balls on the basis of recorded sounds. Recorded sounds were manipulated by merging the temporal characteristics of one sound with the spectral characteristics of another. Perception experiments showed that when subjects had to choose the larger ball from two sounds, they had a preference for the spectral content of a large ball. If subjects had to choose the faster out of two sounds, they preferred the spectral content of a small ball, and, to a lesser degree, the spectral content of a fast rolling ball. The temporal cues in the sounds were of minor importance for the range of stimuli used in this experiment, possibly because sounds with much amplitude modulation and bouncing were excluded from the experiments

On the Use of Sound for Representing Geometrical Information of Virtual Objects

Presented at the 14th International Conference on Auditory Display (ICAD2008) on June 24-27, 2008 in Paris, France.This study is concerned with the use of sound in a multimodal interface that is currently being developed as an aid for product design. By using this interface, the designer is able to physically interact with a virtual object. The requirements of the interface include the interactive sonification of geometrical data, relating to the virtual object, which are otherwise practically undetectable. We propose a classification scheme of the sound synthesis methods relevant to this application. These methods are presented in terms of the level of abstraction between the virtual object and the sound produced as a result of the user's interaction. Finally, we present an example that demonstrates the advantages of sonification for this application

Interactive sonification of curve shape and curvature data

Abstract. This paper presents a number of different sonification approaches that aim to communicate geometrical data, specifically curve shape and curvature information, of virtual 3-D objects. The system described here is part of a multi-modal augmented reality environment in which users interact with virtual models through the modalities vision, hearing and touch. An experiment designed to assess the performance of the sonification strategies is described and the key findings are presented and discussed