4,776 research outputs found

    Fractionally-addressed delay lines

    Full text link
    While traditional implementations of variable-length digital delay lines are based on a circular buffer accessed by two pointers, we propose an implementation where a single fractional pointer is used both for read and write operations. On modern general-purpose architectures, the proposed method is nearly as efficient as the popularinterpolated circular buffer, and it behaves well for delay-length modulations commonly found in digital audio effects. The physical interpretation of the new implementation shows that it is suitable for simulating tension or density modulations in wave-propagating media.Comment: 11 pages, 19 figures, to be published in IEEE Transactions on Speech and Audio Processing Corrected ACM-clas

    Waveguide physical modeling of vocal tract acoustics: flexible formant bandwidth control from increased model dimensionality

    Get PDF
    Digital waveguide physical modeling is often used as an efficient representation of acoustical resonators such as the human vocal tract. Building on the basic one-dimensional (1-D) Kelly-Lochbaum tract model, various speech synthesis techniques demonstrate improvements to the wave scattering mechanisms in order to better approximate wave propagation in the complex vocal system. Some of these techniques are discussed in this paper, with particular reference to an alternative approach in the form of a two-dimensional waveguide mesh model. Emphasis is placed on its ability to produce vowel spectra similar to that which would be present in natural speech, and how it improves upon the 1-D model. Tract area function is accommodated as model width, rather than translated into acoustic impedance, and as such offers extra control as an additional bounding limit to the model. Results show that the two-dimensional (2-D) model introduces approximately linear control over formant bandwidths leading to attainable realistic values across a range of vowels. Similarly, the 2-D model allows for application of theoretical reflection values within the tract, which when applied to the 1-D model result in small formant bandwidths, and, hence, unnatural sounding synthesized vowels

    A hybrid keyboard-guitar interface using capacitive touch sensing and physical modeling

    Get PDF
    This paper was presented at the 9th Sound and Music Computing Conference, Copenhagen, Denmark.This paper presents a hybrid interface based on a touch- sensing keyboard which gives detailed expressive control over a physically-modeled guitar. Physical modeling al- lows realistic guitar synthesis incorporating many expres- sive dimensions commonly employed by guitarists, includ- ing pluck strength and location, plectrum type, hand damp- ing and string bending. Often, when a physical model is used in performance, most control dimensions go unused when the interface fails to provide a way to intuitively con- trol them. Techniques as foundational as strumming lack a natural analog on the MIDI keyboard, and few digital controllers provide the independent control of pitch, vol- ume and timbre that even novice guitarists achieve. Our interface combines gestural aspects of keyboard and guitar playing. Most dimensions of guitar technique are control- lable polyphonically, some of them continuously within each note. Mappings are evaluated in a user study of key- boardists and guitarists, and the results demonstrate its playa- bility by performers of both instruments

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

    Get PDF
    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

    ARTIFICIAL INTELLIGENCE-BASED APPROACH TO MODELLING OF PIPE ORGANS

    Get PDF
    The aim of the project was to develop a new Artificial Intelligence-based method to aid modeling of musical instruments and sound design. Despite significant advances in music technology, sound design and synthesis of complex musical instruments is still time consuming, error prone and requires expert understanding of the instrument attributes and significant expertise to produce high quality synthesised sounds to meet the needs of musicians and musical instrument builders. Artificial Intelligence (Al) offers an effective means of capturing this expertise and for handling the imprecision and uncertainty inherent in audio knowledge and data. This thesis presents new techniques to capture and exploit audio expertise, following extended knowledge elicitation with two renowned music technologist/audio experts, developed and embodied into an intelligent audio system. The Al combined with perceptual auditory modeling ba.sed techniques (ITU-R BS 1387) make a generic modeling framework providing a robust methodology for sound synthesis parameters optimisation with objective prediction of sound synthesis quality. The evaluation, carried out using typical pipe organ sounds, has shown that the intelligent audio system can automatically design sounds judged by the experts to be of very good quality, while significantly reducing the expert's work-load by up to a factor of three and need for extensive subjective tests. This research work, the first initiative to capture explicitly knowledge from audio experts for sound design, represents an important contribution for future design of electronic musical instruments based on perceptual sound quality will help to develop a new sound quality index for benchmarking sound synthesis techniques and serve as a research framework for modeling of a wide range of musical instruments.Musicom Lt

    Real-Time Digital Modeling of Analog Circuitry for Audio Applications

    Get PDF
    The goal of this project was to develop a scalable digital signal processing platform capable of modeling analog audio circuits using state-space modeling techniques. Using circuit theory as a foundation, the analog models were built around time-domain solution of circuit analysis. The resultant platform was capable of indistinguishably modeling variable analog filter circuits, with order being only restricted by hardware capabilities. Various continuous-to-discrete time conversion methods were investigated to determine the optimal sounding and performing algorithm

    Modelling the live-electronics in electroacoustic music using particle systems

    Get PDF
    Contemporary music is largely influenced by technology. Empowered by the current available tools and resources, composers have the possibility to not only compose with sounds, but also to compose the sounds themselves. Personal computers powered with intuitive and interactive audio applications and development tools allow the creation of a vast range of real-time manipulation of live instrumental input and also real-time generation of sound through synthesis techniques. Consequently, achieving a desired sonority and interaction between the electronic and acoustic sounds in real-time, deeply rely on the choice and technical implementation of the audio processes and logical structures that will perform the electronic part of the composition. Due to the artistic and technical complexity of the development and implementation of such a complex artistic work, a very common strategy historically adopted by composers is to develop the composition in collaboration with a technology expert, which in this context is known as a musical assistant. In this perspective, the work of the musical assistant can be considered as one of translating musical, artistic and aesthetic concepts into mathematical algorithms and audio processes. The work presented in this dissertation addresses the problem of choosing, combining and manipulating the audio processes and logical structures that take place on the liveelectronics (i.e the electronic part of a mixed music composition) of a contemporary electroacoustic music composition, by using particle systems to model and simulate the dynamic behaviors that reflect the conceptual and aesthetic principles envisaged by the composer for a determined musical piece. The presented research work initiates with a thorough identification and analysis of the agents, processes and structures that are present in the live-electronics system of a mixed music composition. From this analysis a logical formalization of a typical live-electronics system is proposed, and then adapted to integrate a particle-based modelling strategy. From the formalization, a theoretical and practical framework for developing and implementing live-electronics systems for mixed music compositions using particle systems is proposed. The framework is experimented and validated in the development of distinct mixed music compositions by distinct composers, in real professional context. From the analysis of the case studies and the logical formalization, and the feedback given by the composers, it is possible to conclude that the proposed particle systems modelling method proves to be effective in the task of assisting the conceptual translation of musical and aesthetic ideas into implementable audio processing software.A música contemporânea é amplamente influenciada pela tecnologia. Os recursos tecnológicos atualmente disponíveis permitem que os compositores criem com sons e ao mesmo tempo criem os sons em si próprios. Os atuais aplicativos e ferramentas de software focados no desenvolvimento, controle e manipulação de processamentos de áudio, permitem a elaboração de diversos tipos de tratamentos e sínteses de som com a capacidade de serem executados e manipulados em tempo real. Consequentemente, a escolha dos algoritmos de processamento de áudio e suas respectivas implementações técnicas em forma de software, são determinantes para que a sonoridade desejada seja atingida, e para que o resultado sonoro satisfaça os objetivos estéticos e conceituais da relação entre as fontes sonoras acústicas e os sons eletrônicos presentes em uma composição eletroacústica de caráter misto. Devido à complexidade artística e técnica do desenvolvimento e implementação do sistema de eletrônica em tempo real de uma composição eletroacústica mista, uma estratégia historicamente adotada por compositores é a de desenvolver a composição em colaboração com um especialista em tecnologia, que neste contexto é usualmente referido como assistente musical. Nesta perspectiva, o trabalho do assistente musical pode ser interpretado como o de traduzir conceitos musicais, artísticos e estéticos em algoritmos matemáticos e processamento de áudio. O trabalho apresentado nesta dissertação aborda a problemática da escolha, combinação e manipulação dos processamentos de áudio e estruturas lógicas presentes no sistema de eletrônica em tempo real de uma composição de música eletroacústica contemporânea, e propõem o uso de sistemas de partículas para modelar e simular os comportamentos dinâmicos e morfológicos que refletem os princípios conceituais e estéticos previstos pelo compositor para uma determinada composição. A parte inicial do trabalho apresentado consiste na identificação e análise detalhada dos agentes, estruturas e processos envolvidos na realização e execução do sistema de eletrônica em tempo real. A partir desta análise é proposta uma formalização lógica e genérica de um sistema de eletrônica em tempo real. Em seguida, esta formalização é modificada e adaptada para integrar uma estratégia de modelagem através de sistemas de partículas. Em sequencia da formalização lógica, um método teórico e prático para o desenvolvimento de sistemas de eletrônica em tempo real para composições de música mista é proposto. O teste e consequente validação do método se dá através de sua utilização na realização da eletrônica em tempo real para obras de diferentes compositores. A análise dos casos de estudo e da formalização lógica, e também o parecer e opinião dos compositores, permitem concluir que o método proposto é de fato eficaz na tarefa de auxiliar o processo de tradução dos conceitos musicais e estéticos propostos pelos compositores em forma de algoritmos e processamentos de som implementados em software
    corecore