Thesis

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Sensor shield and fusion algorithm evaluation of DIY Attitude and Heading Reference Systems (AHRS)

Authors Berghold, P.
Year 2020
Thesis Type Audio Engineering project
Topic Audio Signal Processing
Abstract In 2016 binaural syntheses and 3D Audio applications hit the consumer market as firms like google and facebook enabled the possibility for spatial audio playback. To gain a reliable 3D acoustic screen via headphone playback, tracking of the listeners head movements is a necessary feature. Micro Electro Mechanical Systems (MEMS) offer a cheap and sufficient possibility to track such movements, but lack in accuracy. This work evaluates state of the art sensor sheilds and fusion algorithms for the design of an attitude and heading reference system.
Supervisors Rudrich, D.
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Repeated Pitch-shifting for Frequency Discretization as an Artistic Effect for Speech Signals

Authors Planton, M.
Year 2020
Thesis Type Audio Engineering project
Topic Audio Signal Processing
Keywords Computermusic and Elektronic Music, frequency estimation, sound synthesis
Abstract Pitch-shifting effects have been used for a long time, but there are still new innovations to the employed algorithms for fundamental tone analysis (pitch-tracking) and synthesis of a frequency shifted audio signal (pitch-shifting). This project starts with the research on the contemporary pitch-tracking and pitch-shifting algorithms literature, to develop a frequency discretizing pitch-shifting algorithm for monophonic speech signals. Strategies and techniques of the specific design for the effects implementation are discussed. Finally the artistic potential of the effect is evaluated in several applications. So a monophonic speech signal is discretized according to certain pitch scales. The center of this study is the outcome of the repeated application of this audio effect and which possibilities it offers.
Supervisors Höldrich, R.
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Automatischer räumlicher Szenenmischer

Authors Maurer, S., Beck, S.
Year 2020
Thesis Type Audio Engineering project
Topic Audio Signal Processing
Supervisors Frank, M., Rudrich, D.
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Multi-Perspective Scene Analysis from Tetrahedral Microphone Recordings

Authors Blochberger, M.
Year 2020
Thesis Type Master's thesis
Topic Spatial Audio
Keywords audio recording and reproduction, B-format, Higher-Order Ambisonics (HOA), signal processing, Spatial Audio
Abstract Convincing immersion in virtual reality requires to enable the user to engage in interactive listening within three-dimensional audio scenes. To achieve a realistic listening experience, the acoustic perspective and orientation has to be real-time controlled with the own body movements. This thesis addresses the task of presenting an interpolated variable perspective to an interacting listener, while the original audio scene is recorded simultaneously at only a few static perspectives. The scene is decomposed into localizable sound objects and a residual signal for the variable-perspective interpolation. Information regarding localizable objects is extracted from a probability map that is composed from the directions detected by the collective of the available single perspectives. This work proposes a particle-filter-based approach for a continuous position estimation of sound objects. The particle filter uses the probability map to estimate a continuous trajectory for each sound object in the scene. The rendering approach extracts signals from the recording for each localized sound object according to its estimated trajectory and embeds it relative to the virtual listener into the residual signal.
URL https://phaidra.kug.ac.at/o:104549
Supervisors Zotter, F., Höldrich, R.
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Line-source loudspeaker arrays for immersive sound reinforcement

Authors Gölles, L.
Year 2020
Thesis Type Master's thesis
Topic Spatial Audio
Keywords acoustics, Ambisonics, directivity, Spatial Audio, audio reproduction
Abstract The properties of sound systems for three-dimensional sound material are already relatively well understood, as long as the size of the audience remains manageable, i.e. up to about 200 people. For example, the sweet area size for Ambisonic playback systems as usable audience area was examined for direct sound and reverberation. However, such sound systems are already reaching their limits. The sound propagation over longer distances are hardly taken into account by the know studies. According to the current state of the art, sound transmission over large distances is mostly solved by the use of a progressively curved line-source loudspeaker array. This thesis deals with the realization of optimally curved line-source loudspeaker arrays for immersive sound reinforcement in order to guarantee an optimally enveloping/immersive soundscape for the majority of the audience. To this end, this work elaborates a theory of optimally curved line source arrays at different heights and investigates the achievable sound pressure level contour depending on the distance, on the one end. On the other hand, the new theory is evaluated in concluding practical experiments.
Supervisors Zotter, F., Höldrich, R.
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Die gestaltete Schallwelt der Stadt Ein Leitfaden zur nachhaltigen, akustischen Raumplanung

Authors Quade, V.
Year 2020
Thesis Type Master's thesis
Topic Sound and Space
Abstract The acoustic urban space was completely neglected in terms of design just until a few years ago. Although noise control measures are ordered after technical noise measurements, they are not always meaningful for a balanced urban space and often complicate construction considerably. The sustainable soundscape of our future cities is a complex system of physical building measures, traffic planning, individual needs of the residents and the resulting psychoacoustic adjustments of the environment. This work intertwines the components of the system into a guide for those who want to build or approve the city of the future.
URL https://phaidra.kug.ac.at/o:106250
Supervisors Gründler, J.
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EFFEX Sequencer - Implementierung und Erweiterungen von zugrundeliegenden Prinzipien

Authors Wolff, P.
Year 2020
Thesis Type Master's thesis
Topic Sound and Space
Abstract A central approach of the 20th century composition was the creation of new sounds and to expand existing ones. This was achieved by extended playing techniques, prepared instruments and the use of non-traditional equipment. According to this the aesthetic changed. For the first time in history noise was considered as an adequate musical material. Such developments are directly related to technical achievements. They bring along new sounds, ways of thinking, and new genres, as well as new instruments. One example are sequencers, who play an important role in different fields of electronic music. They use internal principles such as repetition, which also represents an essential element of various musical cultures and genres. Within the development of the EFFEX sequencer, attempts were made to pick up underlying functions and limitations of sequencer systems, and alter them by various implementations, such as random operations or expanding the flexibility of rhythmical possibilities. As a result, not only interesting sounds should occur, but also unfamiliar musical structures.
URL https://phaidra.kug.ac.at/o:106249
Supervisors Eckel, G.
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Die Ludische Komposition - Vorstellung einer spielbasierten Form der Interaktivität in der Musik

Authors Scholz, S.
Year 2020
Thesis Type Bachelor's thesis
Topic Sound and Space
URL https://phaidra.kug.ac.at/o:106198.
Supervisors Eckel, G.
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Materiality as a perspective for artistic experimentation

Authors Iadema, G.
Year 2020
Thesis Type Bachelor's thesis
Topic Sound and Space
Abstract This paper proposes a conception of materiality as a perspective for artistic experimentation. It centres on a discussion of a different understanding of the role of materiality in artistic practices. A central point of discussion is the concept of “Absent Matter”, in relation to my project Un_inverso, following the idea of the designer and artist Edoardo Tresoldi. This text aims to present a direct relationship between the concept of matter and the aesthetic of imperfection, more specifically the post glitch aesthetics, by using a comprehensive analysis of the project mentioned above, placed in a larger context. The idea of materiality is applied also to sounds, supported by the drawing on the Heideggerian concept of the thing, outlining a conception of sound as a non-symbolic thing. The proposed idea finds a connection also from an aesthetic point of view. In fact, the use of a glitch aesthetic suggests an idea of transparency, in which the potential and "failures" of technology appears more clearly. They are reflected in basic sounds (click, noise, sinusoids), in direct dialogue with the constituent elements of the project Un_inverso. They are represented by video content and a series of wire mesh models, which have two levels of reading: as constituent elements of architecture (for example, the pillars as regards real models and architectural drawings as regards videos) or as models of complete buildings.
URL https://phaidra.kug.ac.at/o:104785
Supervisors Ciciliani, M.
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Composing and Performing With and Within Feedback Systems

Authors Borsetto, T.
Year 2020
Thesis Type Bachelor's thesis
Topic Sound and Space
Abstract In this thesis I aim at outlining a model of computer music composition as inextricably intertwined with performance and intrinsically bound to the generative qualities of the machine. These qualities are prominent in some specific configurations, for instance in feedback systems. As will be discussed, they appear to be both the cause and the consequence of some specific properties: emergence, non-linearity, complexity and self-organization. My approach is based on the inclusion of these contingencies in the process of composition. As I shall demonstrate, two key elements in this model of computer music composition are the design of the interaction between human and machine, and the mutuality of this interaction, that is the bidirectionality of the exchange of information between the agents. I shall investigate the human, the machine and the bond between them, shaping a narrative along the lines of three key concepts, that are introduced in the very title: composing and performing , with and within and feedback systems .
URL https://phaidra.kug.ac.at/o:104741
Supervisors Eckel, G.
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Welt im Klang: Klangrealitäten und die Entwicklung einer globalen Kompositionspraxis

Authors Bold, J.
Year 2020
Thesis Type Bachelor's thesis
Topic Sound and Space
URL https://phaidra.kug.ac.at/o:104738
Supervisors Eckel, G.
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Street Sound Art

Authors Thomann, I.
Year 2020
Thesis Type Bachelor's thesis
Topic Sound and Space
URL https://phaidra.kug.ac.at/o:104712
Supervisors Eckel, G.
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Block-oriented modeling of nonlinearities in electro-acoustical transducers

Authors Glattfelder, K.
Year 2020
Thesis Type Audio Engineering project
Topic Audio Signal Processing
Keywords audio recording and reproduction, signal processing
Abstract Electro-acoustical transducers, or simply speakers and microphones, are essentially omnipresent throughout everybody's life. The properties and behaviors of these transducers can be analyzed and identified to create models which are used to further refine the quality of the sound or to digitally simulate the identified speaker (e.g. the cabinet of a guitar amplifier with its distinctive sound). One particular aspect of the transducer is its nonlinear behavior, that tends to be especially prominent when operating the speaker at high sound pressure levels (high displacement of the membrane). This “distortion” diminishes the sound quality and can create additional harmonic components that were not originally part of the signal. Although the total amount of the harmonic distortion can be quantified, it is not possible to further characterize the distortion with the conventional identification processes since they only capture the linear behavior. The goal of the current study is creating a python script for block-oriented modeling of nonlinearities in electro-acoustical transducers with Wiener or Hammerstein systems.
Supervisors Höldrich, R.
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Analysis and visualization of bell-ringing

Authors Holzmüller, F.
Year 2020
Thesis Type Audio Engineering project
Topic Audio Signal Processing
Abstract Bell-ringing is a fundamental part of ecclesiastical rites. The aim of this interdisciplinary project involving the long night of churches and the Akademie Graz is to provide a visualization of peal, especially for hearing impaired persons. In a first step, an analysis tool is created. Therefore spectral and temporal features are analyzed including fundamental frequency, harmonic structure, rhythmical motives and dynamic progression. In a next step, a real-time visualization based upon the found parameters is created. A realization of this project is planned for the next long night of churches in Graz.
Supervisors Sontacchi, A.
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Process and Form in Feedback Systems

Authors Pozzi, D.
Year 2019
Thesis Type Master's thesis
Topic Algorithmic Composition
Abstract This thesis presents a model for computer music composition and performance - music instantiated during performance on the basis of stored programs and performance and environmental information. The model is proposed on a view of music composition as an experimental activity, whose results are the consequence of the manifold interactions happening amongst the various agencies involved in its development. In performing a retrospective analysis of one of the author’s most recent works (a live electronics performance entitled CK91) an attempt will be made at unfolding the underlying tapestry of strands and nodes that motivated its development and the choices taken along the way. Some threads and traces, which are considered relevant for their aesthetic and artistic implications, will also be pulled out of the experimental process and discussed from a critical perspective.
URL http://phaidra.kug.ac.at/o:91885
Supervisors Eckel, G.
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Artifices of interdependency

Authors Gagliardi, D.
Year 2019
Thesis Type Master's thesis
Topic Sound and Space
Keywords dynamical systems
Abstract The Live Electronics paradigm in the field of Contemporary Music has often been oriented toward the description or the individuation of a relationship. When the act of composing relies on this practice, the exploration and the constitution of the role of each element which is active in such a network becomes the key of the resulting musical experience. This paradigm is hereby examined in a specific field of application: the relationship between the concrete acoustical world and its digital counterpart. This exploration begins with the definition and the interpretation of these terms, the acknowledgment of what the characteristic of a concrete object are, and the consequent delineation of the boundaries that constrain the concretization of the musical experience. The same importance is given to the description of the methodologies used in this process, which will allow the constitution of interconnections between the different elements. A minor but still relevant theme is the formalization of the performative solutions which will facilitate the listener to take part in the resulting sonic experience, by means of understanding which are the links, hence the forces, which reciprocally act on each other.
URL http://phaidra.kug.ac.at/o:91878
Supervisors Ciciliani, M., Eckel, G.
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Sound generator for rolling- and wind noise

Authors Koch, J.
Year 2019
Thesis Type Master's thesis
Topic Audio Signal Processing
Keywords Sound Design
Abstract Nowadays driving simulators are an important testing tool in the automotive industry. The most important feature is naturally the realistic simulation of the driving feeling. Besides the mechanical/optical simulation, also the realistic soundfield in the driver's cab (which generally consists of engine-, rolling- and wind noises) play an important role. While the mechanical/optical simulation is often a subject of great interest, the realistic soundfield in the driver's cab is rather neglected most of the time. In the course of this master thesis, a sound module for rolling- and wind noise will be developed for Magna Steyr, which will be integrated into an already existing Matlab/Simulink model. By analysing different data sets , a connection between characteristic rolling-/wind noises and driving parameters (such as speed, condition of the road, gear position...) should be established, to subsequently re-synthesize those characteristic noises in Matlab/Simulink by only using these parameters. In addition, a model evaluation/validation through specially adapted listening tests is planned in order to assess the quality of the model and to clarify the question "How important is the rolling/wind noise for a realistic speed impression?"
Supervisors Sontacchi, A.
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Variable-Perspective Rendering of Virtual Acoustic Environments based on Distributed First-Order Room Impulse Responses

Authors Müller, K.
Year 2019
Thesis Type Master's thesis
Topic Spatial Audio
Abstract The Ambisonic spatial decomposition method (ASDM) allows to map first-order room impulse responses (FO RIRs) to higher Ambisonics orders, enhancing a directionally compact and spatially consistent auditory imaging of direct sound and reverberation. Based on this method, the present thesis describes an efficient method for position-dependent interpolation of ASDM-upmixed Ambisonics room impulse responses (ARIRs), measured at multiple perspectives in the room. Linked with an user-interactive ARIR rotation, this approach empowers the listener to move within a virtual acoustic environment with six degrees of freedom (6DoF). In particular, the proposed approach parametrically decomposes the FO RIRs to detect matching early RIR segments of commonly localized source objects from several perspectives. Finally, position-dependent interpolation of matching early RIR segments and linear combination of extrapolated residual RIR parts accomplishes a variable-perspective ARIR for convolution-based Ambisonics audio rendering. To verify the practical usability and relevance of the proposed method, different configurations are evaluated in a listening experiment and compared to a reference.
Supervisors Zotter, F., Höldrich, R.
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Distance-coded Ambisonics Formats and their Reproduction on Headphones and Loudspeaker Arrays

Authors Riedel, S.
Year 2019
Thesis Type Audio Engineering project
Topic Spatial Audio
Abstract This work introduces distance-coded Ambisonics formats and their reproduction on headphones and loudspeaker arrays. The first simple and practically motivated format proposes two ambisonic streams, a far-field and a near-field stream, to which sounds are distributed according to a distance parameter at encoding stage. In binaural decoding this enables the application of near-field HRTFs with inherent binaural cues which cannot be applied at encoding stage, for example the frequency-dependent increase in interaural level differences compared to far-field HRIRs. Blending between two ambisonic reverberation patterns (model or measured DRIR) is combined with a physically meaningful level attenuation to achieve a plausible distance effect that includes a change in the direct-to-reverberant sound energy ratio. Compatibility with loudspeaker arrays is given by combining the two ambisonic streams into one single stream after introducing differences in level and the two reverberation patterns to retain a relative distance effect. An efficient and more accurate way to render distance is to restrict the effect to the horizontal plane. Therefore, a second format that interprets negative elevation as the distance of a horizontal source is proposed. In binaural reproduction, this format allows for a high spatial resolution in the precomputation of distance-dependent HRTFs and early reflections, applied at decoding stage. Moreover, this format could motivate future research on loudspeaker systems that employ horizontal sound field synthesis (rendering of near-field sources) combined with AllRAD for elevated sources.
URL http://phaidra.kug.ac.at/o:92195
Supervisors Höldrich, R.
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Discrimination of short frequency glides depending on reverberation

Authors Brands, B.
Year 2019
Thesis Type Bachelor's thesis
Topic Psychoacoustics
Abstract Differences in phase or group-delay are crucial properties that help the ear to discriminate between short sounds. To obtain further insights in the ability of short-time discrimination of the auditory system, a forced-choice adaptive listening experiment was performed. The subjects were exposed to chirp-like sounds varying in length, direction of the chirp and added reverberation. These chirp-like sounds were rendered by filtering test-signals with an all-pass filter with logarithmic group-delay. The group-delay was varied and the just notable difference (JND) between the logarithmic group-delay of two stimuli was measured. The results depict that by adding more reverberation, the discrimination decreased. Furthermore, upward chirp-like sounds were discriminable in a better way than downward chirp-like sounds and so were short versus long stimulus lengths. The influence of direction was only significant for short durations.
URL http://phaidra.kug.ac.at/o:92193
Supervisors Höldrich, R.
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Tangible user interface for sound field control

Authors Roenisch, T., Haider, M.
Year 2019
Thesis Type Bachelor's thesis
Topic Interaction Design
Keywords Auditory Virtual Environment (AVE)
Abstract Controlling the origin of sound sources in a three-dimensional audio field is a complex task, particularly in a live environment. Since multiple sources can be involved, a good overview, fast access to every source and simple automation commands are required. A user interface should facilitate straightforward handling and situational awareness. The following thesis presents the further development of "A Tangible User Interface for Playing Virtual Acoustics" by Birgit Gasteiger in 2010, with an emphasis on improved usability and advanced Ambisonic-controls and automation. Furthermore, it strives to devine a field of application for the "Tangible User Interface for Auditory Virtual Environments" (TUI-AVE). Several controls for the spatialization of sound sources, the respective development as well as designs of the corresponding visual presentation are outlined.
URL http://phaidra.kug.ac.at/o:92192
Supervisors Ritsch, W.
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Listening experiment on the plausibility of acoustic modeling in virtual reality

Authors Enge, K.
Year 2019
Thesis Type Master's thesis
Topic Audio Signal Processing
Abstract Virtual Reality environments are becoming an increasingly important factor in various applications such as architecture, film, computer games, education, medicine, and therapeutic methods. For a long time, VR applications focused primarily on visual impressions. It is undisputed that three-dimensional sound plays an essential role in the credibility of virtual environments, if only for the reason that real space is largely characterized through its sound. The counterpart of VR glasses for the eyes is binaural reproduction via headphones for the ears. The virtualization of real spaces using programs such as Unity or the Unreal Engine opens up new possibilities for psychoacoustic investigations, namely with binaural rendering in virtual spaces. In the present work, the perceived plausibility of different combinations of visual and acoustic virtualizations of several real spaces was investigated. Twenty participants evaluated these combinations with four different degrees of freedom. Among other things, it is shown that fully dynamic third-order Ambisonics models achieve the same plausibility as models with seventh order. Also, static modeling of the entire reverberation by a convolution of a BRIR reverb delivers similar results as long as the di- rect sound is presented dynamically. The plausibility decreases if the acoustics and the visuals provide a strongly different room size impressions.
URL https://phaidra.kug.ac.at/o:104550
Supervisors Frank, M., Höldrich, R.
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Classification of mechanical noises of motorised cylinder locks

Authors Merz, P.
Year 2019
Thesis Type Audio Engineering project
Topic Audio Signal Processing
Keywords psychoacoustics, Music Information Retrieval
Abstract This thesis examines the classifiability of mechanical noises. The used test data is a set of recordings of motorised cylinder locks, which have been classified according to their build quality. Methods from unsupervised machine learning will be used to study whether it is possible or not to reproduce the classification based on a selection of psychoacoustic features implemented in Python. Finally it will be examined if this classification can also be done automatically.
Supervisors Sontacchi, A.
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Derivative-based regularization of inverse problems in acoustic holography

Authors Pagavino, M.
Year 2019
Thesis Type Master's thesis
Topic Audio Signal Processing
Keywords acoustic holography, acoustic near-field holography
Abstract The visualization of the sound field close to the source is often helpful to understand the vibroacoustic origin. This gave rise to the development of several acoustic imaging techniques that can be used to model the measured sound field radiated by an arbitrary source. One of these models is the equivalent source method (ESM). It models the local sound field by superimposing distributed elementary sources of different strengths. From spatially discrete sound pressure measurements, the strength of these sources can be determined through solving a linear inverse problem. Due to the underdetermined and ill-posed nature of the inverse problem, the introduction of some form of regularization is a prerequisite for obtaining a meaningful solution. Imposing additional constraints on the solution to enforce expected spatial structures can provide suitable regularization. Inverse problems with constraints typically minimize some norm functional acting on the spatial domain. Sparsity promotion through Compressive Sensing, based on L1-norm minimization, has received increasing attention in recent years due to its ability of providing solutions that are valid beyond the spatial sampling limit. However, typical vibroacoustic source phenomena are not necessarily spatially sparse themselves, as they frequently contain spatially distributed patterns as well. This thesis regards regularization methods that impose sparsity on first- and second-order spatial derivatives. This promotes piecewise constant or linear solutions with minimum curvature as a more probable spatial constraint. Such regularizers are heavily used in various fields of image processing. They were only recently introduced in acoustics, where they have consistently proven to effectively model common structures. In this thesis, I propose to adapt the Schatten-norms of the Hessian as regularizers, which to the best of my knowledge has not been considered for acoustic holography yet. What is more, a fused approach is considered where additional sparsity is imposed on the spatial domain, suitable for the characterization of sparse and extended sources. A proximal splitting algorithm is adopted to solve the minimization problem, which allows an efficient implementation of the proposed regularizers. This work provides the fundamental understanding of derivative-based regularization and reveals its characteristics and abilities. The proposed methods are investigated and verified by numerical simulations and by using measurements obtained from an experimental setup. The required theory behind the algorithm is examined and a detailed exposition of its use is provided.
URL http://phaidra.kug.ac.at/o:92568
Supervisors Zotter, F., Höldrich, R.
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Derivative-Based Regulatisation of inverse problems in acoustic holography

Authors Pacher, S.
Year 2019
Thesis Type Bachelor's thesis
Topic Algorithmic Composition