Analysis and resynthesis of polyphonic music

This thesis examines applications of Digital Signal Processing to the analysis, transformation, and resynthesis of musical audio. First I give an overview of the human perception of music. I then examine in detail the requirements for a system that can analyse, transcribe, process, and resynthesise monaural polyphonic music. I then describe and compare the possible hardware and software platforms. After this I describe a prototype hybrid system that attempts to carry out these tasks using a method based on additive synthesis. Next I present results from its application to a variety of musical examples, and critically assess its performance and limitations. I then address these issues in the design of a second system based on Gabor wavelets. I conclude by summarising the research and outlining suggestions for future developments

Textural layers and polyphonic timbre links in electronic dance music

Polyphonic timbre refers to the overall timbral mixture in a music signal. Some of their most salient acoustic dimensions are the Sub-Band Fluxes. Our hypothesis is that there is a temporal alignment between Sub-Band Flux changes and perceived textural layers’ onsets and offsets in electronic dance music (EDM). (i) We asked to 15 professional musicians to record in Reaper every perceived textural layer’s onset or offset of 11 EDM’s tracks, (ii) and calculated the transitional temporal data between homogeneous and successive states of Sub-Band Flux from signals with MIRToolbox functions. Data (i) and (ii) are being correlated. We expect that acoustical timbral changes will show temporal coincidence with perceived textural layers’ onsets and offsets. Results are still in process, and will be discussed in reference to the EDM’s acoustic environment to mutually afford the perception of textural layers and polyphonic timbres.Trabajo publicado en SysMus18. Proceedings of the 11th International Conference of Students of Systematic Musicology. State University of Minas Gerais, Belo Horizonte, 2018.Facultad de Bellas Arte

A Perceptual Investigation into Spatialization Techniques Used in Multichannel Electroacoustic Music for Envelopment and Engulfment

© 2017 Massachusetts Institute of Technology. Composers of electroacoustic music have developed and creatively implemented various spatialization techniques for multichannel loudspeaker setups. What is not known is which of these spatialization techniques is most effective for exploiting the extended creative possibilities available in multidimensional sound. This article discusses an experiment investigating the perception of the spatial attributes of "envelopment" and "engulfment" within a high-density loudspeaker array. The spatialization techniques used in the experiment were timbre spatialization, spectral splitting, amplitude point-source panning, and dynamic spectral subband decorrelation. Three loudspeaker setups, or spatial dimensions, were investigated: horizontal-only; elevated-only; and three-dimensional, which consisted of both horizontal and elevated loudspeaker setups. Results suggest that dynamic spectral subband decorrelation was perceived as both the most enveloping and the most engulfing technique when compared to other techniques in these experimental loudspeaker configurations. We propose that the experimental results can be successfully implemented when composing electroacoustic music to exploit the creative possibilities in a high-density loudspeaker array or in other multichannel loudspeaker configurations

Textural layers and polyphonic timbre links in electronic dance music

Polyphonic timbre refers to the overall timbral mixture in a music signal. Some of their most salient acoustic dimensions are the Sub-Band Fluxes. Our hypothesis is that there is a temporal alignment between Sub-Band Flux changes and perceived textural layers’ onsets and offsets in electronic dance music (EDM). (i) We asked to 15 professional musicians to record in Reaper every perceived textural layer’s onset or offset of 11 EDM’s tracks, (ii) and calculated the transitional temporal data between homogeneous and successive states of Sub-Band Flux from signals with MIRToolbox functions. Data (i) and (ii) are being correlated. We expect that acoustical timbral changes will show temporal coincidence with perceived textural layers’ onsets and offsets. Results are still in process, and will be discussed in reference to the EDM’s acoustic environment to mutually afford the perception of textural layers and polyphonic timbres.Trabajo publicado en SysMus18. Proceedings of the 11th International Conference of Students of Systematic Musicology. State University of Minas Gerais, Belo Horizonte, 2018.Facultad de Bellas Arte

Textural layers and polyphonic timbre links in electronic dance music

Polyphonic timbre refers to the overall timbral mixture in a music signal. Some of their most salient acoustic dimensions are the Sub-Band Fluxes. Our hypothesis is that there is a temporal alignment between Sub-Band Flux changes and perceived textural layers’ onsets and offsets in electronic dance music (EDM). (i) We asked to 15 professional musicians to record in Reaper every perceived textural layer’s onset or offset of 11 EDM’s tracks, (ii) and calculated the transitional temporal data between homogeneous and successive states of Sub-Band Flux from signals with MIRToolbox functions. Data (i) and (ii) are being correlated. We expect that acoustical timbral changes will show temporal coincidence with perceived textural layers’ onsets and offsets. Results are still in process, and will be discussed in reference to the EDM’s acoustic environment to mutually afford the perception of textural layers and polyphonic timbres.Trabajo publicado en SysMus18. Proceedings of the 11th International Conference of Students of Systematic Musicology. State University of Minas Gerais, Belo Horizonte, 2018.Facultad de Bellas Arte

Homogeneity and Heterogeneity: two approaches for designing spatial sound

My research explores the process for designing and reproducing spatial sound through two personal sound-design projects: Pilate (2006) and Metamorphosis42 (2009). Located within the context of design, it explores two modes for spatial sound composition, which at its heart contemplates the potential for the phenomenon of the sound experience to guide the design and reproduction of spatial sound using electroacoustic techniques. The intent is to convey an approach to sound design, by combining the concepts with the tools and techniques used in sound composition, to create an impression of space that is perceived by the listener. This process has enabled me to draw a distinction in approach between my projects, based on the concepts, tools and techniques I apply in the act of making, to guide my work. In emphasising the sound space relation, the notions of the ‘homogeneous’ and the ‘heterogeneous’ emerge. I apply these terms in my research, to embody the essence of a compositional methodology, explored through an analysis of my projects and by engaging with a process of reflection and listening. On this basis, my research suggests that the notion of the ‘homogeneous’ builds on the physical relations of sound and space through an experience of sound within space. If our experience of sound in a real-world scenario can be considered coherent, then, in the context of a sound design process, my research proposes that a ‘homogeneous’ approach to sound composition seeks to faithfully reproduce the perceptually coherent sounding qualities observed in the real-world. This approach is predicated on the fact that the sensations of sound are the result of vibrating materials. The displacement, which occurs at the material surface, creates a pressure wave that moves through the atmosphere interacting with other materials within the environment. As a consequence, the pressure waves that reach our ears come from all directions, not just one and the physical qualities of the materials the pressure wave interacts with – their size, shape and density, for example, directly influence how sound is perceived. The notion of the ‘heterogeneous’ builds on the internal relation of sound and space - the space within sound, and how the physical and imagined qualities of space are interchangeable which conveys a dynamic and complex sense of space. A quality of this approach is that sound is suspended in its own time and space through a poetic re-imagination - an interior space in which sound is decoupled from its physical source. As François Bayle (2007, p.241) writes, ‘a sound from a transducer is like no other’. I interpret this as a way to think about the reproduced sound, which sits beyond the physical. I use the term ‘re-imagination’ to emphasise that the listener is not passive, but instead an active body engaged in this contemplation of sound. On this basis, the heterogeneous is not one singular homogeneous image bound entirely by the physical nature of the source. Instead, it is an affective experience that is bound to our senses and our emotions, reaching our ears through a patchwork of sounds that collide in space and time creating a transformation that occurs at the boundaries of perception

Signal separation of musical instruments: simulation-based methods for musical signal decomposition and transcription

This thesis presents techniques for the modelling of musical signals, with particular regard to monophonic and polyphonic pitch estimation. Musical signals are modelled as a set of notes, each comprising of a set of harmonically-related sinusoids. An hierarchical model is presented that is very general and applicable to any signal that can be decomposed as the sum of basis functions. Parameter estimation is posed within a Bayesian framework, allowing for the incorporation of prior information about model parameters. The resulting posterior distribution is of variable dimension and so reversible jump MCMC simulation techniques are employed for the parameter estimation task. The extension of the model to time-varying signals with high posterior correlations between model parameters is described. The parameters and hyperparameters of several frames of data are estimated jointly to achieve a more robust detection. A general model for the description of time-varying homogeneous and heterogeneous multiple component signals is developed, and then applied to the analysis of musical signals. The importance of high level musical and perceptual psychological knowledge in the formulation of the model is highlighted, and attention is drawn to the limitation of pure signal processing techniques for dealing with musical signals. Gestalt psychological grouping principles motivate the hierarchical signal model, and component identifiability is considered in terms of perceptual streaming where each component establishes its own context. A major emphasis of this thesis is the practical application of MCMC techniques, which are generally deemed to be too slow for many applications. Through the design of efficient transition kernels highly optimised for harmonic models, and by careful choice of assumptions and approximations, implementations approaching the order of realtime are viable.Engineering and Physical Sciences Research Counci

Progressive Filtering Using Multiresolution Histograms for Query by Humming System

The rising availability of digital music stipulates effective categorization and retrieval methods. Real world scenarios are characterized by mammoth music collections through pertinent and non-pertinent songs with reference to the user input. The primary goal of the research work is to counter balance the perilous impact of non-relevant songs through Progressive Filtering (PF) for Query by Humming (QBH) system. PF is a technique of problem solving through reduced space. This paper presents the concept of PF and its efficient design based on Multi-Resolution Histograms (MRH) to accomplish searching in manifolds. Initially the entire music database is searched to obtain high recall rate and narrowed search space. Later steps accomplish slow search in the reduced periphery and achieve additional accuracy. Experimentation on large music database using recursive programming substantiates the potential of the method. The outcome of proposed strategy glimpses that MRH effectively locate the patterns. Distances of MRH at lower level are the lower bounds of the distances at higher level, which guarantees evasion of false dismissals during PF. In due course, proposed method helps to strike a balance between efficiency and effectiveness. The system is scalable for large music retrieval systems and also data driven for performance optimization as an added advantage.Comment: 12 Pages, 6 Figures, Full version of the paper published at ICMCCA-2012 with the same title, Link:http://link.springer.com/chapter/10.1007/978-81-322-1143-3_2