Organisation perceptive dans l'audition

cote interne IRCAM: Botte92aNone / NoneNational audienceNon

Auditory continuity and loudness computation

cote interne IRCAM: McAdams98aNone / NoneNational audienceSequences composed of alternating bursts of different levels with no silences separating them can give rise to a perception of a continuous sound upon which is superimposed an intermittent stream. These experiments soughtt to determine how the perceived loudness of the intermittent stream depends on the level difference between higher-level and lower-level bursts in the sequence in cases in which continuity is either heard or not heard. In the main experiment, listeners were asked to adjust the level of continuous or intermittent comparison sequences to match the loudness of components that appeared to be either continuous or intermittent in an alternating-level reference sequence, thus urging them to focus on the two-stream percept. Loudness matches of the continuous comparison stimulus were close to physical levels of the lower-level bursts, whereas matches of the intermittent comparison stimulus were well below the physical levels of higher-level bursts. These results are discussed in terms of Bregman's [1990, Auditory Scene Analysis, MIT Press, Cambridge, MA

Auditory continuity and loudness computational

Sequences composed of alternating bursts of different levels with no silences separating them can give rise to a perception of a continuous sound upon which is superimposed an intermittent stream. These experiments sought to determine how the perceived loudness of the intermittent stream depends on the level difference between higher-level and lower-level bursts in the sequence in cases in which continuity is either heard or not heard. In the main experiment, listeners were asked to adjust the level of continuous or intermittent comparison sequences to match the loudness of components that appeared to be either continuous or intermittent in an alternating-level reference sequence, thus urging them to focus on the two-stream percept. [...

La perception des sons et de la musique

cote interne IRCAM: Botte95aNone / NoneNational audienceNon

The partitioning of loudness in the auditory continuity phenomenon

cote interne IRCAM: McAdams95bNone / NoneNational audienceNon

Focusing attention on one auditory stream does not depend on the number of simultaneous streams

cote interne IRCAM: Brochard95aNone / NoneNational audienceNon

Perceptual organization of complex auditory sequences: Effect of number of simultaneous sub-sequences and frequency separation

cote interne IRCAM: Brochard99aNone / NoneNational audienceHow do listeners perceptually organize complex auditory sequences composed of two or more simultaneous sub -sequences? We demonstrate that previous results obtained with two-sub-sequence mixtures generalize to more comple x ones, and describe four new organizing principles. A new paradigm identified whether listeners perceive the mixt ure as a single unit (integrative listening) or segregate it into two (or more) perceptual units (stream segregati on). Listeners heard two complex sequences, each composed of 1, 2, 3, or 4 isochronous sub-sequences (each define d by a specific frequency/tempo combination). Their task was to say whether a small temporal irregularity created in one of the sub-sequences was situated in the first or second complex sequence. Attention was focused on one par ticular sub-sequence by preceding the complex sequences by a single sub-sequence. Two control experiments confirm ed that detection was similar in all sub-sequences and was not possible if listeners did not perceptually organize the complex sequences into streams. Then, Experiment 1 showed that the smallest frequency separation under which listeners were able to focus on one sub-sequence was unaffected by the number of co-occurring sub-sequences, sugge sting that the non-focused sounds were not perceptually organized into streams. Experiment 2 showed that temporal detection improved progressively (not abruptly as has been assumed previously) as the frequency separation between the sub-sequences was increased from .25 to 6 auditory filters. Finally, we propose a model of the perceptual org anization of complex auditory sequences

Perceptual attenuation of nonfocused auditory streams

cote interne IRCAM: Botte97a/National audienceThe aim of this study was to measure the perceptual attenuation, measured in decibels, resulting from the focusing of attention on one stream within a multi-stream auditory sequence. The intensity of a non-focused stream was increased until the accuracy of detecting a temporal irregularity in this stream was the same as in a focused stream. Eight subjects were required to detect a temporal irregularity created by delaying or advancing one tone which could be situated in one of three temporally regular streams played simultaneously to create a multi-stream sequence. The three streams differed in tempo and frequency. Subjects' attention was focused on one of the streams by preceding the multi-stream sequence with one of the single streams (a cue). We first established the size of temporal irregularity detected at a 90% level in cued streams, confirming that subjects were able to focus on one particular stream. Second, an irregularity of this size was not detected above chance level in non-cued streams, demonstrating that listeners only focus on the cued stream. Third, for five subjects, a 15 dB increase in the level of one of the non-cued streams was necessary to bring detection up to that found in the cued streams. This gain provides an equivalent measure of the perceptual attenuation of non-focused streams. For three other subjects, detection in the non-cued stream remained at chance performance whatever the level. For all subjects, detection in the cued stream decreased slightly as the level of the non-cued stream increased. We conclude that the attenuation of non-focused auditory streams can attain as much as 15 dB, at least for some subjects

The computation of loudness in the auditory continuity phenomenon

cote interne IRCAM: McAdams94cNone / NoneNational audienceNon