Sound Synthesis for Contact-Driven Musical Instruments via Discretisation of Hamilton's Equations

Physical modelling of musical instruments involves studying nonlinear interactions between parts of the instrument. These can pose several difficulties concerning the accuracy and stability of numerical algorithms. In particular, when the underlying forces are non-analytic functions of the phase-space variables, a stability proof can only be obtained in limited cases. An approach has been recently presented by the authors, leading to unconditionally stable simulations for lumped collision models. In that study, discretisation of Hamilton’s equations instead of the usual Newton’s equation of motion yields a numerical scheme that can be proven to be energy conserving. In this paper, the above approach is extended to collisions of distributed objects. Namely, the interaction of an ideal string with a flat barrier is considered. The problem is formulated within the Hamiltonian framework and subsequently discretised. The resulting nonlinearmatrix equation can be shown to possess a unique solution, that enables the update of the algorithm. Energy conservation and thus numerical stability follows in a way similar to the lumped collision model. The existence of an analytic description of this interaction allows the validation of the model’s accuracy. The proposed methodology can be used in sound synthesis applications involving musical instruments where collisions occur either in a confined (e.g. hammer-string interaction, mallet impact) or in a distributed region (e.g. string-bridge or reed-mouthpiece interaction).

Investigation on the influence of the order on ambisonics reproduced sound scene over headphones

To investigate the performance of ambisonics systems reproduced over headphones, a pairwise comparison test was carried out. Binaurally reproduced sound scenes for 2D ambisonic orders 1 to 4 decoded on 2M + 2 virtual loudspeakers using two decoder options, basic and mixed basic and maxrE were used. Similarity ratings are obtained from pairwise comparisons between all of the combinations of systemsa and a binaural reference.

Belfast Soundwalks: Experiences in Sound and Place through Locative Media

This article outlines the ongoing development of a locative smartphone app for iPhone and Android phones entitled The Belfast Soundwalks Project. Drawing upon a method known as soundwalking, the aim of this app is to engage the public in sonic art through the creation of up to ten soundwalks within the city of Belfast. This paper discusses the use of GPS enabled mobile devices in the creation of soundwalks in other cities. The authors identify various strategies for articulating an experience of listening in place as mediated by mobile technologies. The project aims to provide a platform for multiple artists to develop site-specific sound works which highlight the relationship between sound, place and community. The development of the app and the app interface are discussed, as are the methods employed to test and evaluate the project.

Future Networks - Sound, Space, Performance

Presentation on network performance for the openhere festival in Dublin.

Colloquium on Sound and Music

Invited participation in a colloquium on Sound and Music at CREATIVE RESEARCH INTO SOUND ARTS PRACTICE unit of the London College of Communication.

Distributed Sounding Art – Practices in Distributing Sound (eds. Barry Truax, Marcel Cobussen and Vincent Meelberg)

This chapter examines distributed sounding art by focusing on three key aspects that we consider essentially tied to the notion of distribution: assignment, transport and sharing. These aspects aid us in navigating through a number of nodes in a history of sounding art practices where sound becomes assigned, transported and shared between places and people. Sound or data become distributed, and in the process of distribution, meanings become assigned and altered through differing socio-cultural contexts of places and people. We have selected several works, commencing in the 1960’s as we consider this period as having produced some of the seminal works that address distribution.<br/>We draw on works by composers, performers and sound artists and thus present a history of sounding art, which is amongst the many histories of sounding art in the 20th and 21st century.

Simulation using novel equipment designed to explain spirometric abnormalities in respiratory disease enhances learning in higher cognitive domains

<p>Simulation of disorders of respiratory mechanics shown by spirometry provides insight into the pathophysiology of disease but some clinically important disorders have not been simulated and none have been formally evaluated for education. We have designed simple mechanical devices which, along with existing simulators, enable all the main dysfunctions which have diagnostic value in spirometry to be simulated and clearly explained with visual and haptic feedback. We modelled the airways as Starling resistors by a clearly visible mechanical action to simulate intra- and extra-thoracic obstruction. A narrow tube was used to simulate fixed large airway obstruction and inelastic bands to simulate restriction. We hypothesized that using simulators whose action explains disease promotes learning especially in higher domain educational objectives. The main features of obstruction and restriction were correctly simulated. Simulation of variable extra-thoracic obstruction caused blunting and plateauing of inspiratory flow, and simulation of intra-thoracic obstruction caused limitation of expiratory flow with marked dynamic compression. Multiple choice tests were created with questions allocated to lower (remember and understand) or higher cognitive domains (apply, analyse and evaluate). In a cross-over design, overall mean scores increased after 1½ h simulation spirometry (43-68 %, effect size 1.06, P &lt; 0.0001). In higher cognitive domains the mean score was lower before and increased further than lower domains (Δ 30 vs 20 %, higher vs lower effect size 0.22, P &lt; 0.05). In conclusion, the devices successfully simulate various patterns of obstruction and restriction. Using these devices medical students achieved marked enhancement of learning especially in higher cognitive domains.</p>