Ambisonicss, Binaural Surround, Spatial Audio

Repeatability of head-related transfer function (HRTF) measurements is a critical issue in intra- and inter- laboratory setups. In this paper, simulated perceptual variabilities of HRTFs are computed as an attempt to understand if different acquisition methods achieve similar results in terms of psychoacoustic features. We consider 12 HRTF independent measurement sets of a Neumann KU-100 dummy head from the international round-robin study Club Fritz. Our analysis of HRTF variabilities focuses on localization performance in elevation within the mid-sagittal plane. A round robin evaluation is performed by means of an auditory model which is able to predict elevation errors and front-back confusion for a given pair of target and template HRTF sets. Results report comparable localization performances between four HRTF databases, suggesting that these acquisition methods led to similar performances in providing elevation cues. Such findings further emphasize the intrinsic complexity and the sensitivity of the HRTF measurement process. The final aim of this study is to certify the quality and repeatability of a measurement process at perceptual level; this findings could be extended to the acquisition of human head acoustics.

Eridanus is a 40-minutes-long sci-fi thriller story told through Spatial audio technologies and applied psychoacoustics, using a bespoke 21.4 array of speakers. In a dark black room, an audience of four people is able to experience the performance at one time.

This research and body of work explores how Spatial Audio can be used as a tool for storytelling. There are various media that tell stories relying only on sound, such as radio drama, audio books, and sound installations. These involve different conceptual and technological approaches that allow stories to be told in different ways, such as the use of narration to describe how characters feel, or the environment where they are in. By taking inspiration from Virtual Reality and its 360 degree viewpoint available, this project explores how, using only 360 degree audio, or immersive audio, technically called Spatial Audio, a story can be told.
After an analysis of various forms of digital media and how they use sound to convey meaning, an hybrid narrative format is created, with the aim of realising an entertaining piece of work.

Different Spatial Audio techniques and tools are available for practical use, and various sonic aspects can be used with these, such as the creation of convincing and immersive soundscapes, characters’ ‘sound shapes’, and emotions triggering with sound localisation.

The project involves the development of an original story, building a custom loudspeaker array, an advanced workflow for object-based mixing creation, pre-production, spatial sound design, recording, mixing and presentation.

This thesis concerns the application of psychoacoustic phenomena relating to the non-linear nature of the inner ear as an electroacoustic compositional tool. The compositions included in this portfolio explore the validity of a variety of non-linear inner ear phenomena within composition by employing them as primary compositional devices.

Psychoacoustics research into the non-linearities of the inner ear has proven that the inner ear has much more to offer the composer than has been previously considered. By reversing the role of the ear from, what Christopher Haworth describes as, 'being a submissive receiver',  to becoming an active participant in the creative process, an exciting level of opportunity opens up for both the composer and listener. A focus is given in this research to auditory distortion products and bandwidth phenomena with references to the author's own compositional material.

While it is relatively common for composers to have explored various elements of psychoacoustics in their work, a project of this size, which explicitly explores such material, has not been carried out until now. The work of Maryanne Amacher, Alvin Lucier, Diana Deutsch, and others has highlighted the possibilities of employing psychoacoustic principles in music. This research takes a new approach by placing a direct focus on the benefits of the utilisation of these non-linear mechanisms of the inner ear for the composer, while also positing a number of new creative methodologies with respect to the non-linearities of the inner ear.

Bregman claims that just a 'trickle of studies' in auditory research had been published by the late 1960s. Such a finding coincides with the birth of digital audio, which has facilitated such research to flourish and so the employment of electroacoustic music as an investigative tool into auditory studies seems a natural inclusion into the field.

Adorno once stated that the ear is a 'dozy and inert' organ and, by reconsidering such a view, one can destabilise common assumptions about psychoacoustics and the potential of the ears within music composition.  With a specific focus on phenomena relating to the non-linear biomechanical mechanisms of the inner ear, this research seeks to highlight the added physical dimension that can be experienced by the listener whose ears are being performed.

This research is based on the Binaural rendering from Surround sound. As Binaural and Surround systems are becoming more accurate and able to give a fully-immersive perception of sound through headphones, the importance of understanding how these systems work is necessary to better use, develop, and implement Binaural in the everyday routine. Binaural, its history, features and limitations has been analysed. Surround systems, such as 5.1 and Ambisonics, have been analysed and compared for Binaural Rendering purposes. Ambisonics has shown that its versatility and 360 degrees spatial audio characteristics can be used to accurately render Binaural signals.

The reduction of spatial variation in the quality of reproduced sound within a defined space using varied loudspeaker placements is a significant challenge for sound engineers. Dr Bruce Wiggins has conducted research into encoding, decoding and processing algorithms using Ambisonics, a system based around full-sphere sound reproduction. The outcomes of the research have been made accessible to the wider community by the creation of a suite of software plug-ins (WigWare), a production workflow, and associated teaching materials which can enable commercial audio workstations to benefit from Ambisonics. There are numerous recorded instances of successful use.

This paper presents a multimodal interactive system for non-visual (auditory-haptic) exploration of virtual maps. The system is able to display haptically the height profile of a map, through a tactile mouse. Moreover, spatial auditory information is provided in the form of virtual anchor sounds located in specific points of the map, and delivered through headphones using customized Head-Related Transfer Functions (HRTFs). The validity of the proposed approach is investigated through two experiments on non-visual exploration of virtual maps. The first experiment has a preliminary nature and is aimed at assessing the effectiveness and the complementarity of auditory and haptic information in a goal reaching task. The second experiment investigates the potential of the system in providing subjects with spatial knowledge: specifically in helping with the construction of a cognitive map depicting simple geometrical objects. Results from both experiments show that the proposed concept, design, and implementation allow to effectively exploit the complementary natures of the " proximal " haptic modality and the " distal " auditory modality. Implications for orientation & mobility (O&M) protocols for visually impaired subjects are discussed.

Increasingly more users around the globe use the web browser on a daily basis, in mobile and desktop devices. Recent advances in web technologies allow playback and real-time streaming of audiovisual content within the browser and, in parallel, they allow advanced sound manipulation with the Web Audio API. The work presented here explores the possibilities of sound spatialization, exclusively, with the processing power of the browser.

Navigation within historic spaces requires analysis of a variety of acoustic, proprioceptive and tactile cues; a task that is well-developed in many visually-impaired individuals but for which sighted individuals rely almost entirely on vision. For the visually-impaired, the creation of a cognitive map of a space can be a long process for which the individual may repeat various paths numerous times. While this action is typically performed by the individual on-site, it is of some interest to investigate to what degree this task can be performed off-site using a virtual simulator. We propose a tactile map navigation system with interactive auditory display. The system is based on a paper tactile map upon which the user’s hands are tracked. Audio feedback provides; (i) information on user-selected map features, (ii) dynamic navigation information as the hand is moved, (iii) guidance on how to reach the location of one hand (arrival point) from the location of the other hand (departure point) and (iv) additional interactive 3D-audio cues useful for navigation. This paper presents an overview of the initial technical  development stage, reporting observations from preliminary evaluations with a blind individual. The system will be beneficial to visually-impaired visitors to heritage sites; we describe one such site which is being used to further assess our prototype.

Optimal Source Distribution (OPSODIS) sound-bars are ultimately designed for use in a home listening environment. Previous research has mainly focused on the behavior of the systems at the on-axis position. Theoretically, an OPSODIS sound-bar is capable of reproducing 3D audio to multiple listeners at regular seating interval. Therefore, this paper aims to understand how the listening experience is effected in practically realized system. The cross-talk cancellation of a 2-channel and 3-channel OPSODIS sound-bar was measured at regular intervals from the on-axis position to 600 mm off-axis. This enabled to gain insight into how well binaural signals are reproduced in these areas. Both systems showed periodic areas of high cross-talk cancellation with some degradation in frequency response, suggesting that the sound-bars are appropriate for multi-listener binaural reproduction.

Abstract
This thesis examines the philosophies of auditory spatial perception that can underpin spatial music and explores auditory perception in real and artificial environments. Some theoretical problems are reviewed and their constraining influence on current technological implementation is noted. Progress in manipulating perceptions of direction, distance and movement (of sources and percipients) is reviewed. The “sound field” (via its appeal to interaural differences) as the basis for spatial hearing is rejected as overly-constraining, failing to encapsulate some fundamental meaningful relationships between environment and perceiver.
Cognitive and ecological approaches are considered, and an approach is taken that draws from both. An alternative description of the ontological distinctions that are available in real environments is offered, and the implications for theories of perception are outlined. A modular scheme of spatial perception is proposed, based on the view that causal distinctions in the world influence phylogenetic and ontogenetic development. The thesis describes how these perceptual context modules can be invoked in artificial auditory environments in a process of perceptual cartoonification. Attention is paid to the concept of ambience labelling, a class of information that is extrinsic to the percipient, and which economically appeals to perceptual significance-grading. It is proposed that artificial spatial sound can be managed in terms of causal foreground and background.
This is a novel view that perception engages in modelling causality in a deeply territorial way and so modelling causal consistency in the light of this can provide a flexible and scalable basis for managing artificial spatial sound; some speculations are made about how scale of spatiality might be explored. Modelling the causal field incorporates notions of sensory-fields, but can be extended to provide perceptual interaction.
It is concluded that “music as an environment” qualitatively differs from spatially-arranged sound; its exploration providing useful theoretical supplements to theories of perception.

Project X is an artistic experiment that seeks to investigate the fine line, between acoustic and electronic constructions of sound in space. It is a project with it's primary focus on the creative process. With a focus on developing craftmanship - in a combination of practices such as artistic collaboration, instrumental composition and electronic processing as parameters for creation, the project itself seeks to ask the question: what is artistic process? In a combination of music production, instrumental composition and electronic processing, the music seeks to play with the term authenticity. Can the listener differ between a constructed, and an authentic musical universe? Project X has resulted in four musical pieces: Symphony for 2 flutes, My Authentic Voice, Sandstorm and Move that will be published online in the near future.

While binaural beating is most commonly employed in spatial music and brain entrainment routines, the true potential of this psychoacoustic phenomenon within more traditional methods of electronic composition is often overlooked. A number of sizeable foundation studies have provided an understanding of binaural beating in relation to its scientific nature; however, significantly less is known regarding its application within timbre modulation in music. Timbre modulation can be explored through a combination of varying localization cues alongside spectral components including bandwidth, formant regions, periodic frequency content and phase properties. One of the primary elements of the perception of harmonic and inharmonic material is bandwidth phenomena, which also plays a key role in the perception and creation of binaural beating. By considering these factors, it appears that a direct link can be made between timbre modulation and binaural beating.

Some research exists that explores the relation between monaural beating and Western concepts of consonance and dissonance within composition, however, there is little published material written by composers that directly addresses the application of binaural beating in electroacoustic composition. Consequently, relatively little is known in relation to the finite behaviour (thus, the full potential) of binaural beating within composition and its potential for altering the listener’s perception of timbre.

This study investigated the design and evaluation of a sonification, created for an astronomer who studies exosolar accretion discs. User design methods were applied to sonify data that could allow the classification of accretion discs. The sonification was developed over three stages: a requirements gathering exercise that inquired about the astronomer's work and the data, design and development, as well as an evaluation. Twenty datasets were sonified and analysed. The sonification effectively represented the accretion discs allowing the astronomer to commence a preliminary, comparative classification. Multiple parameter mappings provide rich auditory stimuli. Spatial mapping and movement allow for easier identification of fast changes and peaks in the data which improved the understanding of the extent of these changes.

This interdisciplinary research proposes multichannel electroacoustic systems for recording and playback in immersive environments of sound signals captured in the field, and a method of signal analysis, allowing the spatial location of sound sources in the space around the recording system. In bioacoustics, sound reproduction in an immersive environment could be applied to: (1) recalling the conditions experienced in the field during the recording; (2) experiencing the soundscape produced in loco during the recording, but modifying the position and spatial orientation of the observer and his hearing attention; (3) reconstructing a natural environment acoustically: (3.1) to be shared in a research situation (sending data from sound recordings); (3.2) for remote monitoring in real time (real-time transmission of sound signals from an environment in observation); or (3.3) in the promotion and dissemination of scientific knowledge (e.g. acoustic environments reproduced in science museums). The spatial positioning of each recorded sound source can be determined by comparative analysis of the signal between the different capture points, thus allowing the mapping of the spatial distribution (static or dynamic) of sound sources during the period of the sound capture. In sound arts, these processes and devices open different work opportunities in the field of soundscapes, poetic expressions with spatial features, and may also unfold into the field of sound installations, sound sculptures and even soundtracks for audiovisual, dance and theater. Principles adopted for the creation of devices will be presented, as well as for signal analysis.

... accepted physical and logical standard data formats designed for multi channel surround sound ... Focuseing on the composition of one of his pieces, he describes the ... Canadian Electroacoustic Community (2002) OTONDO, Felipe: "Some considerations for spatial design and ...

After presenting some technological background related to the main subject, contemporary Binaural and Ambisonic tools are discussed. In spite of all the possible applications of both systems, user friendly tools for compositional applications are the main foci of the research.
The first chapter presents the historical and theoretical background behind Ambisonics, binaural systems and head tracking technologies, as well as some recent developments. The main objective of this chapter is to present an overview of previous researches and define how the main subject of the present research has been treated so far. The chapter that follows describe in detail some of the currently available tools for working with three dimensional sounds, their principles and possibilities as described by their developers. The third chapter discuss some experiments realized during the past year and how the tools presented in the second chapter can be put together to build a ‘Virtual Studio’, the difficulties faced during this process, what kind of compromises were required and what assumptions were made in order to make it work intuitively.
Since MAX/MSP is probably the most commonly used software within the academic electronic music composers community, most of the work described was based in this environment in order to allow composers to work in a more intuitive way and to focus on the music itself. MAX/MSP tools are described and analysed as well as recent VST plugins for working in the most popular environment in the music production community outside the academy - digital audio workstations (DAWs). Beyond this, analyses of some of the author`s experiences are reported and some reflections are discussed. Through these discussions, focused on the usage of the previously mentioned tools in practical applications, such as music productions and two case studies related to composition processes, a conclusion points to some future work on binaural reproduction of multichannel systems over headphones.