Acoustic Transparency and the Changing Soundscape of Auditory Mixed Reality

Abstract

Auditory headsets capable of actively or passively intermixing both real and virtual sounds are in-part acoustically transparent. This paper explores the consequences of acoustic transparency, both on the perception of virtual audio content, given the presence of a real-world auditory backdrop, and more broadly in facilitating a wearable, personal, private, always-available soundspace. We experimentally compare passive acoustically transparent, and active noise cancelling, orientation-tracked auditory headsets across a range of content types, both indoors and outdoors for validity. Our results show differences in terms of presence, realness and externalization for select content types. Via interviews and a survey, we discuss attitudes toward acoustic transparency (e.g. being perceived as safer), the potential shifts in audio usage that might be precipitated by adoption, and reflect on how such headsets and experiences fit within the area of Mixed Reality.

Augmenting TV Viewing using Acoustically Transparent Auditory Headsets

“…However, breakthroughs in battery technology, sensing and acoustics are resulting in new forms of personal audio wear which break free of prior limitations of circumaural headphones. Acoustically transparent Auditory Headsets [31] are auditory wearables that have the capability to, either actively or passively, intermix both real and virtual sounds, "not caus[ing] audible modification to the surrounding sound" [46]. Where Nomadic Radio [54] first explored this concept through wearable directional speakers, now we have a variety of circum-and supra-aural (on the ear) Hearables [8,45] and Earables [25,69] reaching consumer hands.…”

“…Bose SoundWear [4], Amazon Echo Loop [17]). And battery technology is such that these headsets are now targeting wearable form factors such that they will have "the capability to infiltrate our everyday lives in ways that visually-oriented AR and VR headsets have yet to fully accomplish, be it for reasons of cost, technological capability, or social acceptability" [31]. Integrated Inertial Measurement Units (IMUs) have become somewhat commonplace, with many headsets utilizing an IMU for head orientation tracking, equivalent to 3DoF consumer VR, for personal spatialized exocentric rendering of sound.…”

“…McGill et al [31] explored both the perception of acoustically transparent audio headwear indoors and outdoors, and their potential usage/adoption. Regarding perception, they found that "in select instances, participants noted that audio delivered via the acoustically transparent frames could appear indistinguishable from reality", with dramatic content noted as being more "part of the real world".…”

“…There is however a comparatively new form of Mixed Reality headset that has the potential to enhance or augment the TV viewing experience non-disruptively, working within the shared and social environment TV is often consumed within. Acoustically transparent Auditory Headsets [31] are effectively the auditory equivalent of a visually-oriented Augmented/Mixed Reality headset, in that they allow the (passive or active) intermixing of both virtual and real-world audio. As a consequence, these headsets allow for listening to occur in ways that are more social and inclusive of the surrounding real-world soundscape e.g.…”

“…listening to music whilst retaining an awareness of the conversation or activities of others in the same space. Notably compared to more traditional visually-oriented MR headsets, acoustically transparent auditory headsets are comparatively affordable, come in form factors that are (arguably) fashionable, and are intended to be wearable all day long [31], such as the Bose Frames (see Figure 1), a pair of glasses with directional speakers integrated into the frames, such that the ear canal is not occluded and virtual audio intermixes with real-world audio. If such headsets see significant adoption, we might expect to again see something of a (more modest) revolution in terms of ubiquitous computing, providing users with a personal, private soundscape that can augment, supplement or in-part supplant their existing aural experiences -a rich new design space for applications and experiences to operate within.…”