This paper introduces a technique that improves the efficiency of the Open Sound Control (OSC) communication protocol. The improvement is achieved by decoupling the user interface and the transmission layers of the protocol, thereby reducing the size of the transmitted data while simultaneously simplifying the receiving end parsing algorithm. The proposed method is fully compatible with the current OSC v1.1 specification. Three widely used OSC toolkits are modified so that existing applications are able to benefit from the improvement with minimal reimplementation efforts, and the practical applicability of the method is demonstrated using a multitouch-controlled audiovisual application. It was found that the required adjustments for the existing OSC toolkits and applications are minor, and that the intuitiveness of the OSC user interface layer is retained while communicating in a more efficient manner.

Discrete-time modelling strategies of analogue Moog sawtooth oscillator waveforms are presented. Two alternative approaches suitable for real-time implementation are proposed, one modelling the analogue waveform in time domain using phase distortion synthesis and another matching the spectrum of an existing antialiasing sawtooth oscillator to the corresponding analogue spectrum using a first-order IIR post-equalising filter. A parameter estimation procedure for both approaches is explained and performed. Performance evaluation using polynomial fits for the estimated parameters is carried out, and good matches between the model outputs and recorded waveforms are obtained. The best match of the tested algorithms is produced by the phase distortion model and by post-equalising the fourth-order B-spline bandlimited step function sawtooth oscillator.

A recently rediscovered sound synthesis method, which is based on feedback amplitude modulation (FBAM), is investigated. The FBAM system is interpreted as a periodically linear time-varying digital filter, and its stability, aliasing, and scaling properties are considered. Several novel variations of the basic system are derived and analyzed. Separation of the input and the modulation signals in FBAM structures is proposed which helps to create modular sound synthesis and digital audio effects applications. The FBAM is shown to be a powerful and versatile sound synthesis principle, which has similarities to the established distortion synthesis methods, but which is also essentially different from them.

This paper focuses on phaseshaping techniques and their relation to classical abstract sound synthesis methods. Elementary polynomial and geometric phaseshapers, such as those based on the modulo operation, linear transformations and piecewise linear phase signals, are investigated. They are then applied to the generation of classic and novel oscillator effects by using nested phaseshaping compositions. New oscillator algorithms introduced in this paper include single-oscillator hard sync, trianglewave modulation, simulated single-oscillator supersaw, and sinusoidal waveshape modulation effects. The digital waveforms produced with phaseshaping techniques are generally discontinuous, which leads to aliasing artifacts. Aliasing can be effectively reduced by modifying samples around each discontinuity using the previously proposed polynomial bandlimited step function (polyBLEP) method.

In this paper we describe the SAME networked platform for context-aware, experience-centric mobile music applications, and we present an implementation of the SAME active music listening paradigm: the Mobile Conductor. It allows the user to express herself in conducting a virtual ensemble playing a MIDI piece of music by means of her mobile phone. The mobile phone detects the user’s hand movement and molds the music performance style by modulating its speed, volume, and intonation.

In designing for engagement at a public multi-touch installation, we identified supporting multiple users and allowing for gradual discovery as challenges. In this paper, we present Worlds of Information, a multi-touch application featuring 3D Worlds, which provide access to different content. These 3D widgets gradually unfold and allow for temporal navigation of multimedia in parallel, while also providing a 2D plane where media can be shared. We report on a field trial at an exhibition using questionnaires and video ethnography. We studied engagement through questions adapted from Flow, Presence and Intrinsic Motivation questionnaires, which showed that users, overall, had a positive and social experience with the installation. The worlds effectively invited multiple users and provided for parallel interaction. While functionality was discovered gradually through social learning, the study demonstrates the challenges of designing multi-touch applications for walk-up-and-use displays.

This paper describes a sound synthesis technique that modulates the coefficients of allpass filter chains using audio-rate frequencies. It was found that modulating a single allpass filter section produces a feedback AM–like spectrum, and that its bandwidth is extended and further processed by non-sinusoidal FM when the sections are cascaded. The cascade length parameter provides dynamic bandwidth control to prevent upper range aliasing artifacts, and the amount of spectral content within that band can be controlled using a modulation index parameter. The technique is capable of synthesizing rich and evolving timbres, including those resembling classic virtual analog waveforms. It can also be used as an audio effect with pitch-tracked input sources.

This is a study on a set of feedback amplitude modulation oscillator equations. It is based on a very simple and inexpensive algorithm which is capable of generating a complex spectrum from a sinusoidal input. We examine the original and five variations on it, discussing the details of each synthesis method. These include the addition of extra delay terms, waveshaping of the feedback signal, further heterodyning and increasing the loop delay. In complement, we provide a software implementation of these algorithms as a practical example of their application and as demonstration of their potential for synthesis instrument design.

This paper surveys a collection of sample applications for networked user-centric context-aware embodied music listening. The applications have been designed and developed in the framework of the EU-ICT Project SAME (www.sameproject.eu) and have been presented at Agora Festival (IRCAM, Paris, France) in June 2009. All of them address in different ways the concept of embodied, active listening to music, i.e., enabling listeners to interactively operate in real-time on the music content by means of their movements and gestures as captured by mobile devices. In the occasion of the Agora Festival the applications have also been evaluated by both expert and non-expert users.

This paper proposes a system for sensor pairing and fusion in an interactive multi-user environment. Using the system, we integrated mobile accelerometer and fixed position optical tracking methods, and implemented two active music listening applications based on the movement interaction from one or more users. We found that an acceleration domain similarity index between the two tracking methods is able to pair the raw interaction streams in near real-time, and that concurrent sampling of the streams allows for easy sensor fusion. Although these algorithms still require further refinement, we believe that combining accurate position with accurate acceleration data is beneficial for novel interactive applications.

Dispersion is a physical phenomenon that makes sound waves more or less inharmonic. Most physical sound synthesis models consider dispersion as a constant property that does not change during the course of a musical event. However, these models would be more expressive without such a restriction. This paper describes a dispersion amount parameter for precise control over inharmonicity, and then experiments with control and audio rate modulation of that parameter. In this research we found that inharmonicity of a plucked string could be smoothly controlled in real-time, and that novel sonic material could be synthesized when the modulation rate was raised into audio range. Instability of the string model with certain parameter values was considered to be problematic.

The synthesis of rich audio spectra requires usually complex source waveforms, large number of simple source components, or increased algorithmic complexity. This paper describes an implementation, which shows that simple elementary bitwise logical operations (OR, AND, XOR) possess power to produce such spectra. Using these operations between two sinusoidal oscillators produced a wide variety of new harmonically related sonic material. The synthesis method is efficient to implement and easily controllable, but it is not generally bandlimited.

Multimedia devices, services, and content are already distributed inside the home network. Mobility, sharing and IP based delivery mechanisms introduce additional challenges to accessibility by extending the range of distribution into interconnected home and Internet scale scenarios. However, the user should be able to access any of these targets in a satisfying, easy, and uniform way despite the differences in target and interaction device technologies. This paper proposes and demonstrates how RESTful and declarative approach could be used in solving extended accessibility and usability problems. In the proposed solution, the network becomes the media center, as one of the networked devices operates as a hub between targets and UI devices, while the actual media is streamed in out of band P2P fashion.

Increased processing power of personal computers has enabled their use as real-time virtual musical instruments. In this thesis, such a software sound synthesizer is designed and implemented, with the main objective being in the development of a composite synthesis architecture comprising several elementary synthesis techniques.

First, a survey of sound synthesis, effects processing and modulation techniques was conducted, followed by an investigation to some existing implementations in hardware and software platforms. Next, a formal object-oriented design methodology was applied to capture the requirements of the implementation, and an architectural design phase was carried out to ensure that the requirements were fulfilled. Thereafter, the actual implementation work was divided between the reusable application framework library and the extended implementation packages. Finally, evaluation of the results was made in form of sound and source code analysis.

As a conclusion, the composite synthesis architecture was found to be relatively intuitive and realizable. The generic object-oriented design methodology applied appeared to be well suited to the design of sound synthesis systems in general, but was considered to be too laborious to follow in every detail. The implementation work benefitted from the properly done design phase, however. The relative amount of man machine interface code compared to other subsystems was still surprisingly large. The timbral dimension of the realizable sound palette appeared to be quite wide, and the quality of the audio output was comparable, or even better than that of the existing implementations.

Audiovisual experiences utilize the parallel nature of auditory and visual perception. Music provides a natural source for the auditory channel, but numerous works have extended the scope of musical material also into the visual domain. However, most installations are either based on specially crafted musical instruments, or on non-interactive, time-domain integration of the two modalities. This paper describes an interactive audiovisual instrument that uses only off-the-shelf hardware and open source software components, to enable simultaneous real-time performance in both auditory and visual channels. The work combines augmented reality and digital audio synthesis techniques in a novel way. Using the system, the performer is able to manipulate both the sound and the visuals of the instrument through playing gestures, and the entire visual appearance of the instrument can be changed by selecting a different sound patch. The system was quite sensitive to lighting conditions however, suggesting the use of alternative tracking methods in actual stage conditions.

Distributed performance occurs when a group of artists and audiences in geographically separated locations collaborate with each other in virtual performance spaces. A pre-requisite for such an event is that the interaction happens in near real time. However, even the highest speed network links have latencies which result lack of presence. This paper investigates the components, causes and tolerance of latency and jitter, and their impact to distributed musical performance. Latency reduction and compensation possibilities are discussed, and audio delay plugin with ping modulated delay time parameter is described, and two experiments using various parameters are conducted. State of the art survey of distributed musical performance software is presented before conclusion.

This video demonstrates semantic music visualization using web technologies and the browser. The techniques consists of Open Sound Control (OSC), Remote XML Events (REX), Server Sent Events (SSE), SVG, XHTML, SMIL, JavaScript and Java. The documentation of the setup is included in the video from 03:11 onwards.

A web server running on a mobile phone can provide access to embedded functionality, personal context and shared user data of the phone. When considering the versatility and distinct features of modern phone models, it may seem that dedicated client applications are required to consume that information. This demonstration abstract shows how a thin middleware layer atop the mobile web server can expose the data and functionality of a mobile phone to existing, widely used third party applications. This can be done non-intrusively, i.e., without modifications in existing client code base, enabling both reuse and enrichment through novel context aware scenarios.

Contemporary personal content libraries can hold tens or even hundreds of thousands media items. It is increasingly difficult to locate individual items from a collection of this magnitude, resulting a great demand for usable and attractive content browsing user interfaces. This paper evaluates 14 consumer oriented media player appliances and applications in order to find common patterns behind their conceptual models, views and UI widgets. The evaluation method is informal, using hands-on testing, user manuals and video review material. Unifying conceptual model is then extended with external content aggregation. It was found that the players have generally identical models, views and widgets, but the look and feel layer allows product differentiation. It might also be beneficial to support non-deterministic and content analysis based methods to augment the basic hierarchical and metadata based browsing model.

In InHoNets project, we have been investigating home entertainment networks from home-to-home interconnectivity and internet content sharing perspective. The aim has been in research of a system where dynamic target infrastructure of networked devices and services can be controlled by heterogeneous remote UI devices. Special attention has been given to utilization of open standard interfaces and techniques. As a concrete result of the research, we have implemented Distributed Media Center (DMC) application, which acts as a convergence hub between controllable targets and remote UI devices (this paper focuses on XHTML-based browser UI). After one year’s effort the work is still in-progress, but we have made some observations which might be of interest to the workshop.