What new experiences and opportunities can be realised by augmenting silent and silenced physical objects with virtual audio content?
In addition to identifying some of the characteristics and experiential qualities of audio augmented objects, this practice-based research project has begun to identify the potential roles that audio augmented objects can play within audio augmented reality experiences [2,12,14]. The research has also identified ways in which collections of audio augmented objects can be used to realise virtual, though physically explorable, soundscapes that can promote interaction and engagement with museums, galleries and heritage sites, their existing collections, spaces and the objects and artefacts within them. Furthermore, audio augmented objects have also demonstrated potential as physical interfaces through which digital audio archival content can be accessed and engaged with.
Recent advances in mobile augmented reality, perhaps most importantly Simultaneous Location and Mapping (SLAM) technology [6,7], have realised precise indoor positioning systems that have enabled a move from the delivery of static binaural audio content to the delivery of dynamic binaural audio content . By tracking a listener’s real-time position and orientation within three-dimensional space it is possible to create a binaural audio listening experience with a greater sense of reality, where audio content delivered through headphones is perceived to exist at precise locations within the listener’s physical environment. By positioning this virtual audio content at the same location as specific physical objects, it can be perceived as emanating from the physical object itself, at times with a fidelity that participants have found hard to distinguish from reality.
As with visually orientated augmented reality experiences, where computer graphics are superimposed over the camera’s image of the physical environment, the presence of the physical object within an audio augmented reality experience can be observed to create a sense of environmental authenticity  which, in turn, adds to the suspension of disbelief, propelling the virtual audio content into reality within the mind of the listener. As such, interesting associations can be made between audio and object, associations which appear to be quite fluid and malleable, and have the potential to be curatorially and creatively exploited.
It also appears that the combination of precise indoor positioning and freely explorable audio-based content helps to realise a naturalistic, intuitive and transparent interface [5,9,16], unobstructed by the screen-based interfaces of visually orientated augmented reality experiences. Additionally, within the context of an exhibition environment, this screenless experience presents the opportunity to augment without visual distraction or interference within these, for the main part, visually orientated real world environments [11,15].
So far, this practice-based, research-through-design approach [3,10] has realised two public-facing interactive sound installations [6,7] and a publicly available audio augmented reality mobile application. The development and deployment of these projects, and the subsequent ethnomethodological analysis of the gathered qualitative data of participants’ interactions and experiences with them [4,8], has provided theoretical insights, developed software, and uncovered best practices for the future application of these types of experiences.
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This author is supported by the Horizon Centre for Doctoral Training at the University of Nottingham (UKRI Grant No. EP/L015463/1).