“…Mariette [63] described audio AR as "simply the introduction of artificial sound material into the real world", with a range of characteristics defining different types of audio AR, such as the predominant sensory modality, the spatial characteristics of the sound, the means of presentation, and user tracking/mobility. Such a broad definition encapsulates many other terms and auditory experiences, from different forms of Spatial and Location Based Audio [63,101,12,62,89,85,68,21] to Mediated Reality and Augmented Perception [99,24,107,104,100,111]. Indeed, even the use of "mobile transistor radios or early portable tape players with headphones could both be understood as presenting an augmented reality" [63] as real and virtual content is combined in both cases.…”