Rhetorical strategies for sound design and auditory display : A case study

IntroductionAuditory Display (AD) and Sonic Interaction Design (SID) are fast growing research domains. The former investigates strategies and modalities for providing information by means of non-verbal sounds. The latter deals with the use of sound in ID. New energies have recently been injected into these fields by a number of European-supported research efforts such as the projects S2S2 (Sound to Sense, Sense to Sound, see http://smcnetwork.org/), CLOSED (Closing the Loop Of Sound Evaluation and Design, see http://closed.ircam.fr/), and the European COST-Action Sonic Interaction Design (see http://sid.soundobject.org/). Nevertheless, it is commonly held within the International Community for Auditory Display (ICAD, see www.icad.org) that AD and SID lack consolidated methodological guidelines.This article proposes rhetoric as a rich repository of principles and techniques and a solid methodological base on which to build new knowledge and expertise in the domains of AD and SID. Classical rhetoric deals with economy and effectiveness of communication through speech. The idea of transferring the tradition and experience of rhetoric from verbal language to another realm is centuries old. Since the 16th century, the transposition of classical rhetorical principles and techniques from the verbal domain to the musical has made an important contribution to the transformation of instrumental music into an independent art form. Instrumental music has since been able to develop its own structures and discourse independently of verbal expression, theatrical representation or dance. Inspired by this example, this study examines the potential to employ musical rhetorical strategies for the design of non-speech audio in the realm of ID and HCI.We argue that what we propose is congruent with a general trend in ID pointing to an increasingly human-centered and ergonomic technology, both physically and psychologically. In this sense, the re-invention and adaptation of communication techniques developed within pure humanistic frameworks to the context of ID seems to be a coherent and promising research strategy in favor of such a general goal.BackgroundSound in IDToday, an increasing number of everyday objects and machines include sonic resources in both an active and a passive sense. This is coherent with the simple fact that our perception of the world is inherently multimodal and that users rarely receive information through only one sensory modality. When feasible, ID applications seek to include several perceptual channels at once. Besides visual and haptic aspects, sound has to be systematically considered in order to pursue a more human-like technology (see, for example, Spence & Zampini, 2006, for the importance of sound in product design). In the near future, we expect to see a multitude of technological devices endowed with expressive and listening capabilities in terms of speech and non-speech audio communication. The envisioned acoustic scenario of the future will include thousands of new artificial sounds that will pervade our everyday life and consume the environmental acoustic bandwidth for the transmission of auditory information. In particular, we expect a huge proliferation of non-verbal sounds, whose advantage is to be pre-attentive, independent of any specific language and, if properly designed, shorter and more intuitive than verbal messages (Brewster, Wright, & Edwards, 1995). Such acoustical hypertrophy requires adequate action aimed at defining ways to best exploit the communication potentialities of non-speech audio, while avoiding the degeneration of the acoustic environment into an overcrowded soundscape. Strategies for designing artificial sounds in a concise and effective way tackle both these aspects at once by optimizing the communication process and reducing the sonic impact in terms of physiological and psychological fatigue. This represents the opposite of what, in the context of alarm design (see Patterson, 1990), an ambulance siren produces. …