Hi, this an article of mine:
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Integrating Spaces: Exploring Granular Synthesis through Tetrahedral Geometry in Spherical Loudspeakers Arrays
Marco Matteo Markidis1
1 Independent Researcher, Parma, Italy
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Abstract. This composition pioneers a speculative approach to sound synthesis by employing tetrahedral geometry within spherical loudspeakers arrays, alongside a distinctive tuning process performed by the interpreter. This process involves identifying frequencies within a defined range that enhance spatial auditory qualities, through modalities like zeroth and first order Ambisonics propagation, thereby tailoring the performance to the unique acoustics of the space. Utilizing a custom-developed granular synthesis technique, realized through a dedicated C++ software, the work invites a recalibration of standard sound synthesis paradigms by intertwining the precise geometry of loudspeakers with the acoustic characteristics of performance spaces. Crucially, the inclusion of a pre-performance, that is a listening-based tuning by the interpreter to align the piece’s frequencies with the room’s acoustical properties, presents a ‘what if’ scenario that reimagines the role of instrumentalists in acousmatic music as active listeners and responders to the environment. Instead of delivering a fixed-media piece, this approach allows for a live, adaptive interplay between the composition, technology, and the unique spatial qualities of each performance environment. The resulting work not only challenges traditional auditory experiences but also opens new avenues for artistic exploration in the integration of sound synthesis, spatial audio, and live performance within music technology.
Keywords: Sound Synthesis, Spatial Audio, Outer-Radiating Spherical Loudspeakers Array, Ambisonics, Tuning Process, Low-order Modes of Propagation, Acousmatic Music, Space Perception
1 Introduction
In the evolving landscape of music technology, where technological advancements incessantly reshape creative practices, “Campi Instabili” pioneers a novel exploration that incorporates tetrahedral geometry within spherical loudspeaker arrays to challenge and enhance spatial auditory experiences. This project not only pushes the boundaries of conventional sound synthesis but integrates granular synthesis technique and spatial audio design to optimize acoustic interactions within varied performance spaces.

The introduction of a custom-developed C++ software bridges technological ingenuity with artistic inquiry, enabling a bespoke synthesization process that tailors soundscapes dynamically to the acoustical properties of each performance location. This shifts the conventional role of performers in acousmatic music to active participants who respond and adjust to their sonic environment, facilitating an immersive and adaptive auditory experience.

2 Conceptual Background and Theoretical Underpinnings

The core idea of “Campi Instabili” draws upon the speculative essence of sound synthesis, uniting computational technologies with philosophical insights on potentiality and aesthetic experience. This initiative goes beyond the limited traditional views by intertwining sound technology with live spatial tuning, exploring the possibilities within acoustic and architectural dynamics.

### 2.1 Speculative Sound Synthesis

The speculative approach in “Campi Instabili” explicitly challenges pre-existing compositional frameworks, proposing instead a dynamic and interactive methodology where sound synthesis becomes an explorative artistic tool rather than just a technical process.

### 2.2 Interdisciplinary Integration

Drawing on principles from acoustics, psychoacoustics, and computational musicology, this project views sound as a complex interplay between physical space and human perception. Utilizing an innovative spherical loudspeaker array, it challenges traditional inward-focused listening experiences by designing outward-radiating soundscapes that redefine spatial dynamics.

### 2.3 Reimagining Musical Composition

Here, musical composition is treated synonymously with sound synthesis, illustrating a shift from traditional composition pathways to a model where integration with the designed hardware is intrinsic to the creative output. This method seamlessly incorporates technology with artistic expression, enhancing both the control over and contingency within the resulting soundscapes.
2.4 Contemporary Music Influences
Drawing from an array of venerable composers and their distinctive approaches to music composition and performance, “Campi Instabili” is deeply informed by a rich tapestry of contemporary musical thought. The piece conceptualizes loudspeakers not merely as mediums of sound projection but as integral performers—akin to traditional instrumentalists—exploring the spatial qualities of their environment. This innovative perspective is inspired by Giorgio Netti’s profound inquiry into what constitutes an instrument, treating it as a “tool to investigate the space.” This notion is vividly integrated into the composition, paralleling the practices of a string instrument performance where interaction with space is intrinsic to the sonic outcome.

Gerard Grisey’s technique, particularly evident during a rehearsal at Villa Medici, where he adjusted the performance tempo of “Les espaces acoustiques” to accommodate the room’s reverberance, profoundly influenced the adaptive approach in “Campi Instabili.” This concept of pre-performance tuning is directly borrowed to allow the piece to resonate harmoniously with the unique acoustics of any given space, questioning traditional rigidity in acousmatic compositions.

Further enriching the piece’s conceptual underpinnings is Agostino Di Scipio’s “Audible Ecosystemics”, which explores the dynamism of live electronics in evolving, self-organizing auditory setups. Likewise, John Cage’s philosophies from “Silence” emphasize the uniqueness of all listening points and the potential of non-conventional performance spaces, which encourages embracing the inherent variability and richness of sonic experiences outside traditional venues.

Iannis Xenakis’s experiments with granular synthesis and Michelangelo Lupone’s work, particularly “Canto di Madre” and “Forma del Respiro”, also serve as significant inspirations. Under Lupone’s mentorship during the advanced master in Electronic Music Composition at Santa Cecilia in Rome, a crucial bottom-up approach in music composition was adopted, emphasizing a granular and foundational buildup in structuring sound—a technique pivotal to the realization of “Campi Instabili.”

3 Design and Development

The design and development of “Campi Instabili” focus on combining advanced sound synthesis techniques with a unique outer-radiating spherical loudspeaker array, known as S.T.One, based on tetrahedral geometry. This geometry is crucial for exploring the complex interplay between zeroth and first order Ambisonics which are vital in achieving the piece’s aesthetic and conceptual goals.

#### 3.1 Hardware Integration

A significant aspect of the project revolves around utilizing the tetrahedral loudspeaker configuration. The S.T.One, with its geometric precision and symmetry, offers an optimal setup for experimenting with different sound placements and transitions essential for exploring the spatial dynamics of sound. The positioning and distance between the speakers are meticulously calculated to optimize auditory effects and control crosstalk, which directly affects the perception of the compositional content.

#### 3.2 Custom Granular Synthesis Development

At the heart of “Campi Instabili” is a custom-built granular synthesis engine specifically crafted for integration with the S.T.One hardware setup. This granulator uses synthetic sine waves manipulated at various phases to match the spatial characteristics dictated by the tetrahedral array. Each grain of sound is enveloped within unique curves tailored to utilize phase relationships effectively between the loudspeakers, enabling the creation of complex auditory phenomena.

#### 3.3 Software Architecture

The granular synthesis software is based on an object-oriented programming paradigm, efficiently encapsulating various audio processing functionalities. This architecture offers flexible manipulation of sound particles, where parameters like grain size, dispersion, and envelope shapes can be dynamically adjusted. Specific classes manage tasks such as audio output and waveform generation, working cohesively to ensure a direct and intuitive link between compositional decisions and their auditory outcomes.

#### 3.4 Integrating the Listening Environment

Adjusting to the acoustic interplay between the loudspeaker array and the surroundings is critical. Tuning sessions adjust frequencies and timbres based on the room’s response to sound propagation, aligning the synthesis with the specific concert space and mirroring traditional practices of tuning instruments to their environment. 

#### 3.5 Rendering and Performance Preparations

The final sound output involves rendering the piece into an A-Format audio file, compatible with the S.T.One system. This conversion process is streamlined to maintain the spatial and timbral nuances designed during the development phase, ensuring high fidelity during live performances.


4 Aesthetic Consideration
The aesthetic framework of “Campi Instabili” centers on exploring new modalities of listening and comprehension within a space influenced by sound technology. This involves a critical engagement with sonic material, spatial characteristics of the environment, and the perceptual faculties of the audience.

#### 4.1 Redefining Spatial Perception

The spatial arrangement in “Campi Instabili” invites the audience to experience sound as a fluid, immersive environment rather than emanating from a localized source. This outer-radiating setup enhances the uncertainty between source and reflection, prompting listeners to navigate the space through auditory cues.

#### 4.2 Sound Materiality and Synthesis

Using purely synthetic sine waves, the sound design focuses on the clarity and purity of tones, highlighting micro-variations that inform the spatial character of the sound. This approach emphasizes textural possibilities and the gestalt phenomena arising from microscopic sonic changes.

#### 4.3 Interactive Composition and Performance

The integration of room acoustics into performance redefines the roles of composer and performer, advocating for a participatory role for performers akin to that of instrumentalists. This transforms the performance into a dynamic interaction between human and computational processes, where both are integral in shaping the auditory experience.

#### 4.4 Audience as Part of the Performance Ecology

Each listener’s unique position within the space suggests a non-dominant acoustic field view, emphasizing an egalitarian approach to auditory experiences. This dynamic engagement encourages continuous renegotiation of auditory perspectives, actively constructing individual auditory experiences through movement and attention.

#### 4.5 Challenging Conventional Aesthetic Experience

By merging sound art with technology, “Campi Instabili” questions traditional musical performance boundaries, engaging critically with the influence of technology on cultural perceptions of sound and space.

5 Analysis and Discussion


“Campi Instabili” manifests an innovative integration of computational sound design and real-time acoustic adaptation, demonstrating how advanced technology can be harmoniously embedded in artistic practices. This project serves as a case study in utilizing speculative art to push the envelope in digital music performance, emphasizing the fluid roles of composer, performer, and technology in creating immersive auditory experiences.

### 5.1 Technology and Space: A Symbiotic Relationship

The project exemplifies how spatial characteristics can actively shape and be shaped by computational sound technologies, illustrating a symbiotic relationship that enhances and personalizes the listener’s experience.

### 5.2 Rethinking Compositional Practice

Reflecting on the speculative nature of the composition, this intervention in traditional music making reveals new pathways for artistic expression where variability and adaptability become central elements.

### 5.3 Broader Implications

Ultimately, “Campi Instabili” not only challenges conventional auditory experiences but also encourages a broader discourse on the role of computational technologies in the future of sound art and music performances, suggesting possibilities for further interdisciplinary studies.
### 5.4 Case Study: Performance in Rome

On September 24, 2023, “Campi Instabili” was performed at the Teatro Studio Borgna within the Auditorium Parco della Musica in Rome, marking the final presentation of a year-long advanced master in Electronic Music Composition. Giuseppe Silvi, the creator of the S.T.One loudspeaker, showcased the composition, which utilized the unique S.T.OneL model. This model employs a truncated tetrahedral design optimized to enhance sound dispersion and promote aural delocalization, critical in achieving the composition’s spatial effects.

During the technical setup, it became apparent that the acoustical dynamics of the live environment differed significantly from the studio conditions. Particularly, the omnidirectional subwoofer signal, initially part of the composition, was found to disrupt the spatial delocalization effect and was subsequently deactivated. This decision highlighted the critical nature of live environmental testing and adjustments.

Throughout the rehearsal and live performance, meticulous attention was paid to refining the sound’s clarity and dispersion, especially in sections featuring granular synthesis. The fine tuning allowed the piece to interact dynamically with the venue’s acoustics, placing the finale’s harmonics effectively at the back of the room, thus enhancing the audience’s spatial experience.

The performance was well-received, prompting discussions around the techniques employed, especially the aspect of sound delocalization. Noteworthy was the conversation with Michele Dall’Ongaro, director of Santa Cecilia, who praised the delocalization technique’s effectiveness. Michelangelo Lupone, a luminary in adaptive electronic composition, also gave positive feedback, drawing parallels with his own experiential sound installations.

Further, the trial use of a tetrahedral Ambisonics microphone provided visual feedback on sound directivity, aligning well with auditory perceptions, and suggesting its utility in future performances and research.

The live setup involved a dedicated computer system running a DAW, connected to a sound card and a power amplifier with built-in speaker equalization filters, exclusively handling the S.T.OneL, thus eliminating the need for a mixer. This setup underscores the composition’s requirement for a precise acoustic design catered to each performance’s unique environmental characteristics.

Reflecting on the performance, the interplay between the audience’s engagement, the acoustic properties of the venue, and the technological setup, provided invaluable insights. These are anticipated to guide future adjustments in the composition and performance practice, particularly in enhancing the clarity and intelligibility of sound in various acoustic conditions, thus pushing the boundaries of spatial audio and performance interaction. This singular live experience, juxtaposed with studio settings, continues to shape the evolving narrative and dramaturgy of listening in “Campi Instabili,” emphasizing its speculative and adaptive essence in the realm of contemporary sound art.
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Here the draft of the chapter "Future Directions":
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Future Directions: An Interdisciplinary Approach to Spatial Sound and Architecture

### Introduction to Framework

Our project’s outcomes have made it abundantly clear that the interplay between sound and architectural space holds immense potential for deepening our understanding of both psychoacoustics and architectural acoustics. To further explore this potential, we propose a comprehensive research framework designed to pioneer novel insights at the intersection of architecture, sound technology, and auditory perception.

### Specific Research Questions

Central to this framework are several pivotal research questions:
- How do architectural variables like shape, material, and size influence the acoustic properties of granular synthesis in situ?
- Can the idiosyncratic acoustics of non-standard architectural spaces enhance the psychoacoustic experience of spatial sound compositions?

These questions aim to uncover the nuanced relationships between architectural design and sound perception, highlighting the transformative potential of their integration.

### Methodological Approach

To address these questions, we propose employing a mixed-methods approach combining empirical acoustic measurements, qualitative listener feedback, and psychoacoustic analysis. This approach will facilitate a robust examination of how sound interacts with varying architectural environments, guiding the design of sound compositions tailored to specific spaces.

### Case Studies and Precedents

Historically, projects such as Iannis Xenakis’ “Polytope de Cluny” have elegantly demonstrated the power of integrating architectural form with sonic elements. Drawing inspiration from such precedents, we plan to document a series of experimental performances in environments ranging from modernist structures to unconventional urban spaces, analyzing how these settings inform and transform the listening experience.

### Anticipated Impact and Relevance

The insights gleaned from this research are expected to have broad implications:
- Academically, providing a deeper understanding of environmental acoustics.
- Culturally, offering new forms of engaging public sound art.
- Practically, informing architectural designs with enhanced acoustic considerations.

### Collaborative and Resource Opportunities

We seek to collaborate with architects, urban planners, and sound artists, creating a dynamic research collective that can fully harness interdisciplinary knowledge. Additionally, partnerships with academic institutions and funding from arts and science grants will be critical for providing the necessary resources and platforms for our studies.

### Challenges, Limitations, and Mitigation Strategies

We anticipate challenges such as varying environmental noise levels and the need for precise audio equipment setups. Strategies such as selecting appropriate times for sound measurement and employing advanced sound isolation techniques will be essential to mitigate these issues.

### Proposed Timeline and Phases

Our preliminary timeline spans three years, divided into phases:
- Year 1: Pilot studies and initial case studies.
- Year 2: Full-scale experimental implementations and data collection.
- Year 3: Analysis, dissemination of findings, and public exhibitions.

### Conclusion: An Invitation for Engagement

We invite researchers, practitioners, and technologists to join us in this endeavor. Together, we can bridge gaps between theoretical research and practical application, enriching both artistic practice and scientific study. This proposed research framework not only addresses pressing questions at the nexus of sound and architecture but also sets the stage for future explorations that could redefine how we perceive and interact with our sonic environments.
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This chapter sounds good to me, however I feel it is slightly disconnected from the previous content. Do you think you can write an updated version, while trying to increase the connection between the article and this draft?