Olivier Houix

Listener Expertise and Sound Identification Influence the Categorization of Environmental Sounds

The influence of listeners expertise and sound identification on the categorization of environmental sounds is reported in three studies. In Study 1, the causal uncertainty of 96 sounds was measured by counting the different causes described by 29 participants. In Study 2, 15 experts and 15 nonexperts classified a selection of 60 sounds and indicated the similarities they used. In Study 3, 38 participants indicated their confidence in identifying the sounds. Participants reported using either acoustical similarities or similarities of the causes of the sounds. Experts used acoustical similarity more often than nonexperts, who used the similarity of the cause of the sounds. Sounds with a low causal uncertainty were more often grouped together because of the similarities of the cause, whereas sounds with a high causal uncertainty were grouped together more often because of the acoustical similarities. The same conclusions were reached for identification confidence. This measure allowed the sound classification to be predicted, and is a straightforward method to determine the appropriate description of a sound.

The Role of Sound Source Perception in Gestural Sound Description

We investigated gesture description of sound stimuli performed during a listening task. Our hypothesis is that the strategies in gestural responses depend on the level of identification of the sound source and specifically on the identification of the action causing the sound. To validate our hypothesis, we conducted two experiments. In the first experiment, we built two corpora of sounds. The first corpus contains sounds with identifiable causal actions. The second contains sounds for which no causal actions could be identified. These corpora properties were validated through a listening test. In the second experiment, participants performed arm and hand gestures synchronously while listening to sounds taken from these corpora. Afterward, we conducted interviews asking participants to verbalize their experience while watching their own video recordings. They were questioned on their perception of the listened sounds and on their gestural strategies. We showed that for the sounds where causal action can be identified, participants mainly mimic the action that has produced the sound. In the other case, when no action can be associated with the sound, participants trace contours related to sound acoustic features. We also found that the interparticipants’ gesture variability is higher for causal sounds compared to noncausal sounds. Variability demonstrates that, in the first case, participants have several ways of producing the same action, whereas in the second case, the sound features tend to make the gesture responses consistent.

Naturalness influences the perceived usability and pleasantness of an interface’s sonic feedback

This study examined the influence of the naturalness of a sonic feedback on the perceived usability and pleasantness of the sounds used in a human-computer interface. The interface was the keyboard of an Automatic Teller Machine. The naturalness of the feedback was manipulated by using different kinds of relationship between a keystroke and its sonic feedback: causal, iconic, and arbitrary. Users were required to rate the naturalness, usability, and pleasantness of the sounds before and after manipulating the interface. Two kinds of interfaces were used: a normally functioning and a defective interface. The results indicated that the different relationships resulted in different levels of naturalness: causal mappings resulted in sounds perceived as natural, and arbitrary mappings in sounds perceived as non-natural, regardless of whether the sounds were recorded or synthesized. Before the subjects manipulated the interface, they rated the natural sounds as more pleasant and useful than the non-natural sounds. Manipulating the interface exaggerated these judgments for the causal and arbitrary mappings. The feedback sounds ruled by an iconic relationship between the user’s gesture and the resulting sounds were overall positively rated, but were sensitive to a potential contamination by the negative feelings created by a defective interface.

Sonically Augmented Artifacts: Design Methodology Through Participatory Workshops

Participatory workshops have been organized within the framework of the ANR project Legos that concerns gesture-sound interactive systems. These workshops addressed both theoretical issues and experimentation with prototypes. The first goal was to stimulate new ideas related to the control of everyday objects using sound feedback, and then, to create and experiment with new sonic augmented objects. The second aim was educational. We investigated how sonic interaction design can be introduced to people without backgrounds in sound and music. We present in this article an overview of three workshops. The first workshop focused on the analysis and the possible sonification of everyday objects. New usage scenarios were obtained and tested. The second workshop focused on sound metaphor, questioning the relationship between sound and gesture. The last one was a workshop organized during a summer school for students. During these workshops, we experimented a cycle of design process: analysis, creation and testing.

Innovative Tools for Sound Sketching Combining Vocalizations and Gestures

Designers are used to produce a variety of physical and digital representations at different stages of the design process. These intermediary objects (IOs) do support the externalization of ideas and the mediation with the different stakeholders. In the same manner, sound designers deliver several intermediate sounds to their clients, through iteration and refinement. In fact, these preliminary sounds are sound sketches representing the intermediate steps of an evolving creation. In this paper we reflect on the method of sketching sounds through vocalizations and gestures, and how a technological support, grounded in the understanding of the design practice, can foster transparency and mediation in sound design-thinking. Three tools, under development in the scope of the EU project SkAT-VG (Sketching Audio Technologies using Vocalizations and Gestures) are introduced and discussed, based on the preliminary observations collected during a workshop involving professional sound designers.