SOUND SYNTHESIS WITH CELLULAR AUTOMATA

This thesis reports on new music technology research which investigates the use of cellular automata (CA) for the digital synthesis of dynamic sounds. The research addresses the problem of the sound design limitations of synthesis techniques based on CA. These limitations fundamentally stem from the unpredictable and autonomous nature of these computational models. Therefore, the aim of this thesis is to develop a sound synthesis technique based on CA capable of allowing a sound design process. A critical analysis of previous research in this area will be presented in order to justify that this problem has not been previously solved. Also, it will be discussed why this problem is worthwhile to solve. In order to achieve such aim, a novel approach is proposed which considers the output of CA as digital signals and uses DSP procedures to analyse them. This approach opens a large variety of possibilities for better understanding the self-organization process of CA with a view to identifying not only mapping possibilities for making the synthesis of sounds possible, but also control possibilities which enable a sound design process. As a result of this approach, this thesis presents a technique called Histogram Mapping Synthesis (HMS), which is based on the statistical analysis of CA evolutions by histogram measurements. HMS will be studied with four different automatons, and a considerable number of control mechanisms will be presented. These will show that HMS enables a reasonable sound design process. With these control mechanisms it is possible to design and produce in a predictable and controllable manner a variety of timbres. Some of these timbres are imitations of sounds produced by acoustic means and others are novel. All the sounds obtained present dynamic features and many of them, including some of those that are novel, retain important characteristics of sounds produced by acoustic means

Computational musicology: An Artificial Life approach

Abstract — Artificial Life (A-Life) and Evolutionary Algorithms (EA) provide a variety of new techniques for making and studying music. EA have been used in different musical applications, ranging from new systems for composition and performance, to models for studying musical evolution in artificial societies. This paper starts with a brief introduction to three main fields of application of EA in Music, namely sound design, creativity and computational musicology. Then it presents our work in the field of computational musicology. Computational musicology is broadly defined as the study of Music with computational modelling and simulation. We are interested in developing A-Life-based models to study the evolution of musical cognition in an artificial society of agents. In this paper we present the main components of a model that we are developing to study the evolution of musical ontogenies, focusing on the evolution of rhythms and emotional systems. The paper concludes by suggesting that A-Life and EA provide a powerful paradigm for computational musicology. I

Non-Standard Sound Synthesis with Dynamic Models

Full version unavailable due to 3rd party copyright restrictions.This Thesis proposes three main objectives: (i) to provide the concept of a new generalized non-standard synthesis model that would provide the framework for incorporating other non-standard synthesis approaches; (ii) to explore dynamic sound modeling through the application of new non-standard synthesis techniques and procedures; and (iii) to experiment with dynamic sound synthesis for the creation of novel sound objects. In order to achieve these objectives, this Thesis introduces a new paradigm for non-standard synthesis that is based in the algorithmic assemblage of minute wave segments to form sound waveforms. This paradigm is called Extended Waveform Segment Synthesis (EWSS) and incorporates a hierarchy of algorithmic models for the generation of microsound structures. The concepts of EWSS are illustrated with the development and presentation of a novel non-standard synthesis system, the Dynamic Waveform Segment Synthesis (DWSS). DWSS features and combines a variety of algorithmic models for direct synthesis generation: list generation and permutation, tendency masks, trigonometric functions, stochastic functions, chaotic functions and grammars. The core mechanism of DWSS is based in an extended application of Cellular Automata. The potential of the synthetic capabilities of DWSS is explored in a series of Case Studies where a number of sound object were generated revealing (i) the capabilities of the system to generate sound morphologies belonging to other non-standard synthesis approaches and, (ii) the capabilities of the system of generating novel sound objects with dynamic morphologies. The introduction of EWSS and DWSS is preceded by an extensive and critical overview on the concepts of microsound synthesis, algorithmic composition, the two cultures of computer music, the heretical approach in composition, non- standard synthesis and sonic emergence along with the thorough examination of algorithmic models and their application in sound synthesis and electroacoustic composition. This Thesis also proposes (i) a new definition for “algorithmic composition”, (ii) the term “totalistic algorithmic composition”, and (iii) four discrete aspects of non-standard synthesis

Methodology for the production and delivery of generative music for the personal listener : systems for realtime generative music production

This thesis will describe a system for the production of generative music through specific methodology, and provide an approach for the delivery of this material. The system and body of work will be targeted specifically at the personal listening audience. As the largest current consumer of music in all genres of music, this represents the largest and most applicable market to develop such a system for. By considering how recorded media compares to concert performance, it is possible to ascertain which attributes of performance may be translated to a generative media. In addition, an outline of how fixed media has changed how people listen to music directly will be considered. By looking at these concepts an attempt is made to create a system which satisfies societies need for music which is not only commodified and easily approached, but also closes the qualitative gap between a static delivery medium and concert based output. This is approached within the context of contemporary classical music. Furthermore, by considering the development and fragmentation of the personal listening audience through technological developments, a methodology for the delivery of generative media to a range of devices will be investigated. A body of musical work will be created which attempts to realise these goals in a qualitative fashion. These works will span the development of the composition methodology, and the algorithmic methods covered. A conclusion based on the possibilities of each system with regard to its qualitative output will form the basis for evaluation. As this investigation is seated within the field of music, the musical output and composition methodology will be considered as the primary deciding factor of a system's feasibility. The contribution of this research to the field will be a methodology for the composition and production of algorithmic music in realtime, and a feasible method for the delivery of this music to a wide audience

L-Music: uma abordagem para composição musical assistida usando L-Systems

Generative music systems have been researched for an extended period of time. The scientific corpus of this research field is translating, currently, into the world of the everyday musician and composer. With these tools, the creative process of writing music can be augmented or completely replaced by machines. The work in this document aims to contribute to research in assisted music composition systems. To do so, a review on the state of the art of these fields was performed and we found that a plethora of methodologies and approaches each provide their own interesting results (to name a few, neural networks, statistical models, and formal grammars). We identified Lindenmayer Systems, or L-Systems, as the most interesting and least explored approach to develop an assisted music composition system prototype, aptly named L-Music, due to the ability of producing complex outputs from simple structures. L-Systems were initially proposed as a parallel string rewriting grammar to model algae plant growth. Their applications soon turned graphical (e.g., drawing fractals), and eventually they were applied to music generation. Given that our prototype is assistive, we also took the user interface and user experience design into its well-deserved consideration. Our implemented interface is straightforward, simple to use with a structured visual hierarchy and flow and enables musicians and composers to select their desired instruments; select L-Systems for generating music or create their own custom ones and edit musical parameters (e.g., scale and octave range) to further control the outcome of L-Music, which is musical fragments that a musician or composer can then use in their own works. Three musical interpretations on L-Systems were implemented: a random interpretation, a scale-based interpretation, and a polyphonic interpretation. All three approaches produced interesting musical ideas, which we found to be potentially usable by musicians and composers in their own creative works. Although positive results were obtained, the developed prototype has many improvements for future work. Further musical interpretations can be added, as well as increasing the number of possible musical parameters that a user can edit. We also identified the possibility of giving the user control over what musical meaning L-Systems have as an interesting future challenge.Sistemas de geração de música têm sido alvo de investigação durante períodos alargados de tempo. Recentemente, tem havido esforços em passar o conhecimento adquirido de sistemas de geração de música autónomos e assistidos para as mãos do músico e compositor. Com estas ferramentas, o processo criativo pode ser enaltecido ou completamente substituído por máquinas. O presente trabalho visa contribuir para a investigação de sistemas de composição musical assistida. Para tal, foi efetuado um estudo do estado da arte destas temáticas, sendo que foram encontradas diversas metodologias que ofereciam resultados interessantes de um ponto de vista técnico e musical. Os sistemas de Lindenmayer, ou L-Systems, foram selecionados como a abordagem mais interessante, e menos explorada, para desenvolver um protótipo de um sistema de composição musical assistido com o nome L-Music, devido à sua capacidade de produzirem resultados complexos a partir de estruturas simples. Os L-Systems, inicialmente propostos para modelar o crescimento de plantas de algas, são gramáticas formais, cujo processo de reescrita de strings acontece de forma paralela. As suas aplicações rapidamente evoluíram para interpretações gráficas (p.e., desenhar fractais), e eventualmente também foram aplicados à geração de música. Dada a natureza assistida do protótipo desenvolvido, houve uma especial atenção dada ao design da interface e experiência do utilizador. Esta, é concisa e simples, tendo uma hierarquia visual estruturada para oferecer uma orientação coesa ao utilizador. Neste protótipo, os utilizadores podem selecionar instrumentos; selecionar L-Systems ou criar os seus próprios, e editar parâmetros musicais (p.e., escala e intervalo de oitavas) de forma a gerarem excertos musicais que possam usar nas suas próprias composições. Foram implementadas três interpretações musicais de L-Systems: uma interpretação aleatória, uma interpretação à base de escalas e uma interpretação polifónica. Todas as interpretações produziram resultados musicais interessantes, e provaram ter potencial para serem utilizadas por músicos e compositores nos seus trabalhos criativos. Embora tenham sido alcançados resultados positivos, o protótipo desenvolvido apresenta múltiplas melhorias para trabalho futuro. Entre elas estão, por exemplo, a adição de mais interpretações musicais e a adição de mais parâmetros musicais editáveis pelo utilizador. A possibilidade de um utilizador controlar o significado musical de um L-System também foi identificada como uma proposta futura relevante

Ηχητικά Είδη: Ηλεκτροακουστική σύνθεση με Στοιχειώδη Κυτταρικά Αυτόματα και Game of Life

Τα κυτταρικά αυτόματα ως υπολογιστικό μοντέλο εντοπίζονται, μέσω των συνεχώς αυξανόμενων εφαρμογών τους, σε ένα εύρος επιστημονικών κλάδων και τεχνών. Το χαρακτηριστικότερο γνώρισμα των κυτταρικών αυτομάτων είναι η δυνατότητα απρόβλεπτης συμπεριφοράς η οποία όμως προκύπτει ή αναδύεται από πολύ απλούς κανόνες. Τα είδη αυτομάτων στα οποία μπορεί κανείς να παρατηρήσει με σαφήνεια τη συμπεριφορά που περιγράφουμε είναι αυτά που ακολουθούν και τους απλούστερους κανόνες. Για το λόγο αυτό επιλέξαμε να χρησιμοποιήσουμε για τη μουσική δημιουργία τα στοιχειώδη κυτταρικά αυτόματα (elementary cellular automata) και το Game of Life, δυο συστήματα με πολύ απλές αρχές λειτουργίας. Η μελέτη των συστημάτων αυτών έγινε παράλληλα με τη διερεύνηση του διεπιστημονικού υποβάθρου αλλά και συναφών φιλοσοφικών εννοιών όπως αυτή της ανάδυσης και του δυισμού μορφής - ύλης που έχουν αφετηρία τις θεωρίες του Αριστοτέλη. Ως το μεγαλύτερο μέρος της εργασίας αυτής, δημιουργήθηκε ένα μουσικό έργο σε δύο μέρη τα οποία αποτελούν δύο ξεχωριστές εκτελέσεις σε ένα σύστημα που δημιουργήσαμε στο Max/MSP όπου αξιοποιούνται δύο αλγόριθμοι στοιχειωδών κυτταρικών αυτομάτων και το Game of Life παράλληλα. Βαρύτητα ιδιαίτερη δόθηκε στη δυνατότητα των μερών του συστήματος να επικοινωνούν μεταξύ τους με τρόπο που να αποφεύγεται η προβλεψιμότητα αλλά και η αίσθηση της τυχαιότητας στο μουσικό αποτέλεσμα.Cellular automata as a computational model can be found, through their constantly increasing applications, in a wide field of studies and arts. Typical trait of cellular automata is the capability of producing unpredictable behaviour which, however, comes or emerges from simple rules. The kinds of cellular automata in which one can observe with clarity their behaviour, is the ones that follow the simplest rules. That is why we chose the Elementary Cellular Automata and the Game of Life in order to create music. The study of these systems was done in parallel with researching of the interdisciplinary background as well as relevant philosophical notions, such as that of Emergence and the dualism of Form – Matter which derive from Aristotle’s theories. As the major part of this thesis, a musical work in two parts was made with a Max/MSP system that uses algorithms for Elementary Cellular Automata and the Game of Life, in parallel. From a musical perspective, the focal point was placed in the capability of communication between different parts of the system in a way that either predictability or complete randomness is avoided

Da emergência da sonoridade às sonoridades emergentes: mediação tecnológica, emergentismo e a criação sonora com suporte computacional

Apresentamos uma visão panorâmica e crí­tica de como o uso computador enquanto artefato de criação musical pode retroagir sobre os próprios modelos composicionais mediados por este. De maneira similar às mudanças de paradigma que o uso de dispositivos de gravação trouxe à criação musical, emergindo disto a sonoridade como um aspecto central do discurso sonoro, o uso de computadores tem potencializado novos campos de ação criativa não orientados à determinação das estruturas da obra em si, mas à criação de condições ambientais favoráveis ao surgimento de estruturas como um aspecto emergente da própria interação entre as partes do sistema. A partir da discussão de distintos modelos composicionais, trataremos como a criação com suporte computacional tem sido explorada como aporte à emergência de novas estruturas

Adaptive music: Automated music composition and distribution

Creativity, or the ability to produce new useful ideas, is commonly associated to the human being; but there are many other examples in nature where this phenomenon can be observed. Inspired by this fact, in engineering, and particularly in computational sciences, many different models have been developed to tackle a number of problems. Music, a form of art broadly present along the human history, is the main field addressed in this thesis, taking advantage of the kind of ideas that bring diversity and creativity to nature and computation. We present Melomics, an algorithmic composition method based on evolutionary search, with a genetic encoding of the solutions, which are interpreted in a complex developmental process that leads to music in the standard formats. This bioinspired compositional system has exhibited a high creative power and versatility to produce music of different type, which in many occasions has proven to be indistinguishable from the music made by human composers. The system also has enabled the emergence of a set of completely novel applications: from effective tools to help anyone to easily obtain the precise music they need, to radically new uses like adaptive music for therapy, amusement or many other purposes. It is clear to us that there is much research work yet to do in this field; and that countless and new unimaginable uses will derive from it

Real-time sound synthesis on a multi-processor platform

Real-time sound synthesis means that the calculation and output of each sound sample for a channel of audio information must be completed within a sample period. At a broadcasting standard, a sampling rate of 32,000 Hz, the maximum period available is 31.25 μsec. Such requirements demand a large amount of data processing power. An effective solution for this problem is a multi-processor platform; a parallel and distributed processing system. The suitability of the MIDI [Music Instrument Digital Interface] standard, published in 1983, as a controller for real-time applications is examined. Many musicians have expressed doubts on the decade old standard's ability for real-time performance. These have been investigated by measuring timing in various musical gestures, and by comparing these with the subjective characteristics of human perception. An implementation and its optimisation of real-time additive synthesis programs on a multi-transputer network are described. A prototype 81-polyphonic-note- organ configuration was implemented. By devising and deploying monitoring processes, the network's performance was measured and enhanced, leading to an efficient usage; the 88-note configuration. Since 88 simultaneous notes are rarely necessary in most performances, a scheduling program for dynamic note allocation was then introduced to achieve further efficiency gains. Considering calculation redundancies still further, a multi-sampling rate approach was applied as a further step to achieve an optimal performance. The theories underlining sound granulation, as a means of constructing complex sounds from grains, and the real-time implementation of this technique are outlined. The idea of sound granulation is quite similar to the quantum-wave theory, "acoustic quanta". Despite the conceptual simplicity, the signal processing requirements set tough demands, providing a challenge for this audio synthesis engine. Three issues arising from the results of the implementations above are discussed; the efficiency of the applications implemented, provisions for new processors and an optimal network architecture for sound synthesis

Emergent Rhythmic Structures as Cultural Phenomena Driven by Social Pressure in a Society of Artificial Agents

This thesis studies rhythm from an evolutionary computation perspective. Rhythm is the most fundamental dimension of music and can be used as a ground to describe the evolution of music. More specifically, the main goal of the thesis is to investigate how complex rhythmic structures evolve, subject to the cultural transmission between individuals in a society. The study is developed by means of computer modelling and simulations informed by evolutionary computation and artificial life (A-Life). In this process, self-organisation plays a fundamental role. The evolutionary process is steered by the evaluation of rhythmic complexity and by the exposure to rhythmic material. In this thesis, composers and musicologists will find the description of a system named A-Rhythm, which explores the emerged behaviours in a community of artificial autonomous agents that interact in a virtual environment. The interaction between the agents takes the form of imitation games. A set of necessary criteria was established for the construction of a compositional system in which cultural transmission is observed. These criteria allowed the comparison with related work in the field of evolutionary computation and music. In the development of the system, rhythmic representation is discussed. The proposed representation enabled the development of complexity and similarity based measures, and the recombination of rhythms in a creative manner. A-Rhythm produced results in the form of simulation data which were evaluated in terms of the coherence of repertoires of the agents. The data shows how rhythmic sequences are changed and sustained in the population, displaying synchronic and diachronic diversity. Finally, this tool was used as a generative mechanism for composition and several examples are presented.Leverhulme Trus