This paper describes a software package for auralisation in interactive virtual reality environments. Its purpose is to reproduce, in real time, the 3D soundfield within a virtual room where listener and sound sources can be moved freely. Output sound is presented binaurally using headphones. Auralisation is based on geometric acoustic models combined with head-related transfer functions (HRTFs): the direct sound and reflections from each source are computed dynamically by the image-source method. Directional cues are obtained by filtering these incoming sounds by the HRTFs corresponding to their propagation directions relative to the listener, computed on the basis of the information provided by a head-tracking device. Two interactive real-time applications were developed to demonstrate the operation of this software package. Both provide a visual representation of listener (position and head orientation) and sources (including image sources). One focusses on the auralisation-visualisation synchrony and the other on the dynamic calculation of reflection paths. Computational performance results of the auralisation system are presented.

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Spatial audio playback solutions provide video game players with ways to experience more immersive and engaging video game content. This paper aims to find whether listening systems that are able to more accurately convey spatial information are preferred by video game players, and to what extent this is true for different loudspeaker configurations whilst engaged in video game play. Results do suggest that a listening system with high perceived spatial quality is more preferred.

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The APEX system [1] enables vocal tract articulation using a reduced set of user controllable parameters by means of Principal Component Analysis of X-ray tract data. From these articulatory profiles it is then possible to calculate cross-sectional area function data that can be used as input to a number of articulatory based speech synthesis algorithms. In this paper the Kelly-Lochbaum 1-D digital waveguide vocal tract is used, and both APEX control and synthesis engine have been implemented and tested in SuperCollider. Accurate formant synthesis and real-time control are demonstrated, although for multi-parameter speech-like articulation a more direct mapping from tract-to-synthesizer tube sections is needed. SuperCollider provides an excellent framework for the further exploration of this work.

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This paper presents an experiment comparing player performance in a gamified localisation task between three loudspeaker configurations: stereo, 7.1 surround-sound and an equidistantly spaced octagonal array. The test was designed as a step towards determining whether spatialised game audio can improve player performance in a video game, thus influencing their overall experience. The game required players to find as many sound sources as possible, by using only sonic cues, in a 3D virtual game environment. Results suggest that the task was significantly easier when listening over a 7.1 surround-sound system, based on feedback from 24 participants. 7.1 was also the most preferred of the three listening conditions. The result was not entirely expected in that the octagonal array did not outperform 7.1. It is thought that, for the given stimuli, this may be a repercussion due to the octagonal array sacrificing an optimal front stereo pair, for more consistent imaging all around the listening space.

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Timbre is a crucial element of believable and natural binaural synthesis. This paper presents a method for diffuse-field equalisation of first-order Ambisonic binaural rendering, aiming to address the timbral disparity that exists between Ambisonic rendering and head related transfer function (HRTF) convolution, as well as between different Ambisonic loudspeaker configurations. The presented work is then evaluated through listening tests, and results indicate diffuse-field equalisation is effective in improving timbral consistency.

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This paper contains the results of a study making use of a set of B-format soundscape recordings, presented in stereo UHJ format as part of an online listening test, in order to investigate the relationship between soundscape categorisation and subjective evaluation. Test participants were presented with a set of soundscapes and asked to rate them using the Self-Assessment Manikin (SAM) and in terms of three soundscape categories: natural, human, and mechanical. They were also asked to identify the important sound sources present in each soundscape. Results show significant relationships between soundscape categorisation and the SAM, and indicate particularly significant sound sources that can affect these ratings.

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Soundscape research is concerned with the study and understanding of our relationship with our surrounding acoustic environments and the sonic elements that they are comprised of. Whilst much of this research has focussed on sound alone, any practical application of soundscape methodologies should consider the interaction between aural and visual environmental features: an interaction known as cross-modal perception. This presents an avenue for soundscape research exploring how an environment’s visual features can affect an individual’s experience of the soundscape of that same environment. This paper presents the results of two listening tests1 : one a preliminary test making use of static stereo UHJ renderings of first-order-ambisonic (FOA) soundscape recordings and static panoramic images; the other using YouTube as a platform to present dynamic binaural renderings of the same FOA recordings alongside full motion spherical video. The stimuli for these tests were recorded at several locations around the north of England including rural, urban, and suburban environments exhibiting soundscapes comprised of many natural, human, and mechanical sounds. The purpose of these tests was to investigate how the presence of visual stimuli can alter soundscape perception and categorisation. This was done by presenting test subjects with each soundscape alone and then with visual accompaniment, and then comparing collected subjective evaluation data. Results indicate that the presence of certain visual features can alter the emotional state evoked by exposure to a soundscape, for example, where the presence of ‘green infrastructure’ (parks, trees, and foliage) results in a less agitating experience of a soundscape containing high levels of environmental noise. This research represents an important initial step toward the integration of virtual reality technologies into soundscape research, and the use of suitable tools to perform subjective evaluation of audiovisual stimuli. Future research will consider how these methodologies can be implemented in real-world applications.

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