The HOA library, review and prospects

International audienceIn this paper, we present the HOA Library, an open source high order ambisonic spatialisation tools collection programmed in C++. We expose the objectives and characteristics of the project, which treat the potential of high order Ambisonics in a musical perspective, based on the practice and the creativity of the electronic musicians. We clarify the context of use, the choice of optimization and decoding. We review the implementations of thelibrary in various environments, such Max, Pure Data, and Faust. We discuss the use of feedback from musicians and members of especially Max and Pure Data community. Finally, we advance the prospects of the HOA library in its current developments in three dimensions

Pandemics, Delays, and Pure Data: on 'afterlives' (2020), for Flute and Live Electronics and Visuals

The essay addresses creative and technical aspects of the piece 'afterlives' (2020), for flute and live electronics and visuals. Composed and premiered in the context of the COVID-19 pandemic, the composition employs audiovisual processes based on different audiovisual techniques: phase-vocoders, buffer-based granulations, Ambisonics spatialization, and variable delay of video streams. The resulting sounds and images allude to typical situations of social interaction via video conferencing applications. 'Afterlives' relies on an interplay between current, almost-current, and past moments of the audiovisual streams, which dephase the performer's images and sounds. I have avoided, in text, delving deeper into the Pure Data abstractions and or into the musical analysis of my composition. The main purpose of the text is rather to present compositional/technical elements of 'afterlives' and discuss how they enable new experiences of time

User experience in an interactive music virtual reality system: An exploratory study

The Objects VR interface and study explores interactive music and virtual reality, focusing on user experience, understanding of musical functionality, and interaction issues. Our system offers spatio-temporal music interaction using 3D geometric shapes and their designed relationships. Control is provided by tracking of the hands, and the experience is rendered across a head-mounted display with binaural sound presented over headphones. The evaluation of the system uses a mixed methods approach based on semi-structured interviews, surveys and video-based interaction analysis. On average the system was positively received in terms of interview self-report, metrics for spatial presence and creative support. Interaction analysis and interview thematic analysis also revealed instances of frustration with interaction and levels of confusion with system functionality. Our results allow reflection on design criteria and discussion of implications for facilitating music engagement in virtual reality. Finally our work discusses the effectiveness of measures with respect to future evaluation of novel interactive music systems in virtual reality

Music in Virtual Space: Theories and Techniques for Sound Spatialization and Virtual Reality-Based Stage Performance

This research explores virtual reality as a medium for live concert performance. I have realized compositions in which the individual performing on stage uses a VR head-mounted display complemented by other performance controllers to explore a composed virtual space. Movements and objects within the space are used to influence and control sound spatialization and diffusion, musical form, and sonic content. Audience members observe this in real-time, watching the performer\u27s journey through the virtual space on a screen while listening to spatialized audio on loudspeakers variable in number and position. The major artistic challenge I will explore through this activity is the relationship between virtual space and musical form. I will also explore and document the technical challenges of this activity, resulting in a shareable software tool called the Multi-source Ambisonic Spatialization Interface (MASI), which is useful in creating a bridge between VR technologies and associated software, ambisonic spatialization techniques, sound synthesis, and audio playback and effects, and establishes a unique workflow for working with sound in virtual space

Studying the perception of sound in space : granular sounds spatialized in a high-order ambisonics system

Space is an important aspect of music composition that received little emphasis in certain periods of the history of Western music. However, in the twentieth century, electroacoustic music reintroduced this element by utilizing the different spatialization methods available. In this article, we discuss the methodology of analysis and the results of a study of the perception of sound in space involving sounds generated by granular synthesis that were spatialized in a high-order ambisonics system performed at CIRRMT’s Immersive Presence Laboratory at McGill University. We investigated two hypotheses of sound perception in space: 1) the variation of the granular synthesis parameters produces differences in the morphology of sounds perceived in their time-varying spatial distribution; and 2) the presence of more morphological sound variations when higher orders of ambisonics are employed, in addition to the generation of sound fields with more depth. In order to verify these hypotheses, we employed a method of analysis based on graphical representations of data derived from audio descriptors, such as graphical curves, a graphic representation of volume and phase space graphics. As a result, we observed that when higher orders of ambisonics are employed, the listener perceives more variations in frequency and intensity in sound spatialization, in addition to a preponderance of the decorrelation effect. Such effect is related to the presence of more diffuse sound fields262CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP304431/2018-4; 429620/2018-72016/23433-

Trajectoires : une application mobile pour le contrôle et l’écriture de la spatialisation sonore

International audienceIn this paper, we explore the potential of mobile devices for the control and the composition of sound spatialization. We conducted interviews with four composers to understand their needs and guide the design of a new mobile application that allows the drawing of sound sources trajectories. We describe three collaborations with composers who appropriated the application to create trajectories and integrate them into their creations.Dans cet article, nous explorons les possibilités offertes par les dispositifs mobiles pour le contrôle et l'écriture de la spatialisation sonore. Nous avons réalisé des entre-tiens avec quatre compositeurs pour comprendre leurs besoins et guider la conception d'une nouvelle application mobile permettant le dessin de trajectoires de sources sonores. Nous décrivons des collaborations avec trois compositeurs qui se sont appropriés l'application pour créer des trajectoires et les intégrer dans leurs créations

Projetando o espectro do som no espaço: imagens-movimento de parciais e grãos sonoros

Enquanto o tempo é sempre mencionado como característica inerente à música, o espaço na maioria das vezes não é tratado como categoria operatória da composição, algo que mudou de figura durante o século XX devido a novas abordagens composicionais e teóricas. Esteartigo apresenta a construção de um instrumento digital em Max/MSP maleável a diferentes configurações de difusão sonora e congregando diferentes possibilidades de síntese com espacialização em ambissonia de ordem superior, com o intuito de integrar o espectro do som à espacialização na música eletroacústica (acusmática ou mista) pela projeção de parciais e/ou grãos em movimento no espaço de difusão. Para tanto, são apresentados osseguintes referenciais teóricos: 1) abordagens históricas do espaço na composição musical com ênfase nos séculos XX e XXI; 2) o sistema Ambisonics; e 3) uma conceituação sobre os modelos sonoros ondulatório e granular, dessa forma situando a proposta na área da criação musical para sistemas com grande densidade de alto- -falantes. Como resultados, apresento as ferramentas de composição e espacialização incluídas no instrumento digital desenvolvido, além do experimento composicional Imagens transdutivas. Como conclusão, esboça-se uma reflexão sobre a percepção sonora em sistemas imersivos a partir das ideias de imagem-movimento e blocos de espaço-tempo

Effects of reverberation conditions and physical versus virtual source placement on localization in virtual sound environments

Sound field synthesis systems vary in number and arrangement of loudspeakers and methods used to generate virtual sound environments to study human hearing perception. While previous work has evaluated the accuracy with which these systems physically reproduce room acoustic conditions, less is known on assessing subjective perception of those conditions, such as how well such systems preserve source localization. This work quantifies the accuracy and precision of perceived localization from a multi-channel sound field synthesis system at Boys Town National Research Hospital, which used 24 physical loudspeakers and vector-based amplitude panning to generate sound fields. Short bursts of broadband speech-shaped noise were presented from source locations (either coinciding with a physical loudspeaker location, or panned between loudspeakers) under free-field and modeled reverberant-room conditions. Listeners used a HTC Vive remote laser tracking system to point to the perceived source location.Results show that the system synthesizes source locations accurately for both physical and panned sources, in both azimuth and elevation. Panned sources, though, are localized less precisely than physical sources. Reverberant condition is also found to affect both the accuracy and precision of localization in the azimuthal plane, with dry conditions producing greater accuracy and better precision. Only accuracy (not precision) of localization in elevation was impacted by reverberant condition, with reverberant cases producing results closer to the target than dry cases. An interaction effect of reverberant condition with elevation on localization in elevation, though, indicates that dry conditions result in better localization in elevation than reverberant ones at an elevation close to head height, but the situations at higher elevations are where subjects localized dry sources lower than the target height, while reverberant ones were more accurately placed. Other laboratories with sound field synthesis systems are encouraged to gather similar data on the accuracy and precision of localization in azimuth and elevation, so that results from studies using these systems can be better interpreted in light of the capabilities of the system to generate accurate and precise reproductions of source locations. [Work supported by NIH GM109023.] Advisor: Lily M. Wan

Interdependent Compositions Employed in Sonic Ecosystems: Integrating the Listener in the Evolving Soundscape

A presente dissertação explora a integração de ouvintes na paisagem sonora em transformação enquanto compositores do ambiente sónico, no formato de instalações áudio.A investigação é motivada pela necessidade de promover e discutir a identidade do património aural da cidade do Porto e a sua crescente transformação.O desenho metodológico seguido é o practice-led research/research-led practice, e foca-se na compreensão e no desenvolvimento de ecossistemas sonoros e das relações interdependentes entre os agentes internos e externos do sistema.Os participantes exploram cartografias sonoras generativas, transformando iterativamente a natureza composicional das paisagens ao navegarem por motivos abrangentes ou focarem em elementos específicos da experiência.Palavras-chave: Identidade, Transformação, Ecossistema, Composição de Paisagens Sonoras, Interatividade.This dissertation explores the integration of listeners in the evolving soundscape as compositional agents of the sonic environment, presented as an audio installation.The investigation is motivated by the need to promote and discuss the sonic landscape identity of Porto and its rapid transformation. A method of practice-led research/research-led practice is followed, focusing on the development and understanding of sonic ecosystems and the interdependent relationships between its internal and external agents.Participants explore generative aural cartographies, transforming iteratively the nature of compositions by expanding into wider motifs or focusing on small and specific elements of the experience.Keywords: Identity, Transformation, Ecosystem, Soundscape Composition, Interactivity