Surround by Sound: A Review of Spatial Audio Recording and Reproduction

In this article, a systematic overview of various recording and reproduction techniques for spatial audio is presented. While binaural recording and rendering is designed to resemble the human two-ear auditory system and reproduce sounds specifically for a listener’s two ears, soundfield recording and reproduction using a large number of microphones and loudspeakers replicate an acoustic scene within a region. These two fundamentally different types of techniques are discussed in the paper. A recent popular area, multi-zone reproduction, is also briefly reviewed in the paper. The paper is concluded with a discussion of the current state of the field and open problemsThe authors acknowledge National Natural Science Foundation of China (NSFC) No. 61671380 and Australian Research Council Discovery Scheme DE 150100363

Proceedings of the EAA Spatial Audio Signal Processing symposium: SASP 2019

International audienc

Cognitive performance in open-plan office acoustic simulations: Effects of room acoustics and semantics but not spatial separation of sound sources

The irrelevant sound effect (ISE) characterizes short-term memory performance impairment during irrelevant sounds relative to quiet. Irrelevant sound presentation in most laboratory-based ISE studies has been rather limited to represent complex scenarios including open-plan offices (OPOs) and not many studies have considered serial recall of heard information. This paper investigates ISE using an auditory-verbal serial recall task, wherein performance was evaluated for relevant factors in simulating OPO acoustics: the irrelevant sounds including the semanticity of speech, reproduction methods over headphones, and room acoustics. Results (Experiments 1 and 2) show that ISE was exhibited in most conditions with anechoic (irrelevant) nonspeech sounds with/without speech, but the effect was substantially higher with meaningful speech compared to foreign speech, suggesting a semantic effect. Performance differences in conditions with diotic and binaural reproductions were not statistically robust, suggesting limited role of spatial separation of sources. In Experiment 3, statistically robust ISE were exhibited for binaural room acoustic conditions with mid-frequency reverberation times, T30 (s) = 0.4, 0.8, 1.1, suggesting cognitive impairment regardless of sound absorption representative of OPOs. Performance differences in T30 = 0.4 s relative to T30 = 0.8 and 1.1 s conditions were statistically robust. This emphasizes the benefits for cognitive performance with increased sound absorption, reinforcing extant room acoustic design recommendations. Performance differences in T30 = 0.8 s vs. 1.1 s were not statistically robust. Collectively, these results suggest that certain findings from ISE studies with idiosyncratic acoustics may not translate well to complex OPO acoustic environments

Spatial auditory display for acoustics and music collections

PhDThis thesis explores how audio can be better incorporated into how people access information and does so by developing approaches for creating three-dimensional audio environments with low processing demands. This is done by investigating three research questions. Mobile applications have processor and memory requirements that restrict the number of concurrent static or moving sound sources that can be rendered with binaural audio. Is there a more e cient approach that is as perceptually accurate as the traditional method? This thesis concludes that virtual Ambisonics is an ef cient and accurate means to render a binaural auditory display consisting of noise signals placed on the horizontal plane without head tracking. Virtual Ambisonics is then more e cient than convolution of HRTFs if more than two sound sources are concurrently rendered or if movement of the sources or head tracking is implemented. Complex acoustics models require signi cant amounts of memory and processing. If the memory and processor loads for a model are too large for a particular device, that model cannot be interactive in real-time. What steps can be taken to allow a complex room model to be interactive by using less memory and decreasing the computational load? This thesis presents a new reverberation model based on hybrid reverberation which uses a collection of B-format IRs. A new metric for determining the mixing time of a room is developed and interpolation between early re ections is investigated. Though hybrid reverberation typically uses a recursive lter such as a FDN for the late reverberation, an average late reverberation tail is instead synthesised for convolution reverberation. Commercial interfaces for music search and discovery use little aural information even though the information being sought is audio. How can audio be used in interfaces for music search and discovery? This thesis looks at 20 interfaces and determines that several themes emerge from past interfaces. These include using a two or three-dimensional space to explore a music collection, allowing concurrent playback of multiple sources, and tools such as auras to control how much information is presented. A new interface, the amblr, is developed because virtual two-dimensional spaces populated by music have been a common approach, but not yet a perfected one. The amblr is also interpreted as an art installation which was visited by approximately 1000 people over 5 days. The installation maps the virtual space created by the amblr to a physical space

Perceptual Optimization of Room-In-Room Reproduction with Spatially Distributed Loudspeakers

It is often desirable to reproduce a specific room-acoustic scene, e.g. a concert hall in a playback room, in such a way that the listener has a plausible and authentic spatial impression of the original sound source including the room acoustical properties. In this study a perceptually motivated approach for spatial audio reproduction is developed. This approach optimizes the spatial and monaural cues of the direct and reverberant sound separately. More specifically, the (monaural) spectral cues responsible for the timbre and the (binaural) interaural cross correlation (IACC) cues, responsible for the listener envelopment, were optimized in the playback room to restore the auditory impression of the recording room. The direct sound recorded close to the source is processed with an auditory motivated gammatone filterbank such that the spectral cues, ITD’s and ILD’s are comparable to the direct sound in the recording room. Additionally, the reverberant sound, which was recorded at two distant locations from the source, is played back via dipole loudspeakers. Due to the arrangement of the two dipole loudspeakers, only the diffuse sound field in the playback room is excited, therefore the spectral cues and the IACC of the reverberant sound field can be controlled independently to match the cues that were present in the recording room. As indicated by a preliminary listening test the applied optimization is perceptually similar to the reference signal and is generally preferred when compared to a conventional room-in-room reproduction.DFG, FOR 1732, Individualisierte Hörakustik: Modelle, Algorithmen und Systeme für die Sicherstellung der akustischen Wahrnehmung für alle in allen Situatione

Sound effect metaphors for near field distance sonification

International audienceThis article presents a concept of distance sound source sonification for virtual auditory displays in the context of the creation of an assistive device for the visually impaired. In order to respond to user needs, three sonification metaphors of distance based on sound effects were designed. These metaphors can be applied to any type of sound and thereby satisfy all aesthetic desires of users. The paper describes the motivation to use this new type of sonification based on sound effects, and proposes guidelines for the creation of these three metaphors. It then presents a user evaluation of these metaphors by 16 subjects through a near field sound localization experiment. The experiment included a simple binaural rendering condition in order to compare and quantify the contribution of each metaphor on the distance perception