Church Belles

'Church Belles' is a composition that makes use of an interactive music system to accompany a guitarist/vocalist. The system is realised as a separate machine entity that is able to influence the creative process in composition and performance through 'performative' (real-time) and 'memetic' (non-real-time) agency (Bown et al, 2009) . The use of a real-world metaphor (church bells) is a strategy for increasing audience engagement through enhancing the liveness (Sanden, 2013) of the performance. While interactive systems have been extensively used in the performance of improvisatory, experimental music (Rowe, 1993) their use in fixed-form popular music is much less common. The importance of audience experience is also becoming increasingly recognised (Reeves et al, 2005).

Models based on real-world metaphors for interactive, generative machine performers have included models of masses on springs (Johnston et al, 2008), dynamic fluids (Johnston, 2013), rotating strings (Gurevich, 2014) and virtual objects in 3D virtual reality (Zappi et al, 2011). The use of real-world metaphors offers several advantages, particularly when working with a human performer. These include a shared mental model of the system between system designer, performer and audience (Biles, 2013) that represent “embodied understanding” (Mainsbridge and Beilharz, 2014). Such systems facilitate simple, intuitive mappings of human performance data to system behaviour – for example, a specific pitch can be mapped to a specific object in the physical system. The velocity of the note can be directly mapped to a force exerted on an object (Johnston et al, 2008). This circumvents the problem of processing large amounts of gestural input data into multiple parameters and devising complex mappings to the workings of generative algorithms (Visi et al, 2014).

Church bells were selected as a metaphor due to the potential of their simple workings to be recreated in software as a transparent, audio-visual system, their thematic richness for compositional exploration and their ability to produce chaotic rhythms and melodies. The basic system was implemented using jit.phys objects in Cycling '74's Max. The ten bells of Notre Dame were used as the basis for the pitch of each bell. To enhance the transparency of the system, the virtual bells were sized and arranged according to pitch . Specific notes detected in the guitar signal ‘ring’ a particular bell via a virtual force (impulse) on its body. When the movement of the bell causes an impact between the body and the clapper, a MIDI note is sent to samplers and synthesizers to generate the bell’s sound. This action also pitch-shifts the live vocal of the human performer to create additional vocal layers according to the pitch of the sounding bell. A score-following mechanism, analogous to the system’s knowledge of the piece of music and based on the incoming MIDI notes, was implemented. Detection of a sectional change alters the bells’ behaviour and the system outputs.

This work contributes to the field by offering new perspectives into the process of working with interactive systems (e.g. Chadabe, 1984) as well as exploring theories of liveness in a practice-based research framework.

A standalone version of the system has been created as a 'Musebot'. This is able to interact with other autonomous software agents in a Musebot ensemble either as a performance or as an installation (Eigenfeldt, 2016).

Performed at:
• MTI concert series, De Montfort University (2016)
• International Festival of Artistic Innovation, Leeds (2016)
• Sonorities, Queen’s University (2016)
• Sound and Music Computing Conference, Hamburg (2016) - As part of 'Musebot' installation.

Related papers:
• Waite, S. (2016) Church Belles: An Interactive System and Composition Using Real-World Metaphors. Proceedings of New Interfaces for Musical Expression. Brisbane, Australia. Available at: http://www.nime.org/proceedings/2016/nime2016_paper0052.pdf
• Waite, S. (2017) Interactivity and Liveness in Popular Music. Innovations in Music, London, UK.
• Waite, S. (2017) The Use of Metaphor in Interactive Systems for Singer-Songwriters. Tracking the Creative Process in Music, Huddersfield, UK.

Video available at:
http://vimeo.com/152642239
http://www.youtube.com/watch?v=mDGnFQj1MUw

References
Biles, J. (2013). Performing with Technology: Lessons Learned from the GenJam Project. In: Musical Metacreation: Papers from the 2013 AIIDE Workshop. 2013, Boston, MA.
Bown, O., Eldridge, A. & McCormack, J. (2009). Understanding Interaction in Contemporary Digital Music: from instruments to behavioural objects. Organised Sound. 14 (02). p.pp. 188–196.
Chadabe, J. (1984). Interactive Composing: An Overview. Computer Music Journal. 8 (1). p.pp. 22–27.
Cycling ’74 (n.d.). Max is a visual programming language for media. | Cycling ’74. [Online]. Available from: https://cycling74.com/products/max/. [Accessed: 29 January 2016].
Eigenfeldt, A. (2016), “Musebots at One Year: A Review”, in Proceedings of 4th International Workshop on Musical Metacreation, Paris, France.
Johnston, A. (2013). Fluid Simulation as Full Body Audio-Visual Instrument. In: Proceedings of NIME 2013. 2013, Daejeon, South Korea, pp. 132–135.
Johnston, A., Candy, L. & Edmonds, E. (2008). Designing and evaluating virtual musical instruments: facilitating conversational user interaction. Design Studies. 29 (6). p.pp. 556–571.
Mainsbridge, M. & Beilharz, K. (2014). Body as Instrument – Performing with Gestural Interfaces. In: Proceedings of the International Conference on New Interfaces for Musical Expression. 2014, London, UK, pp. 110–113.
Reeves, S., Benford, S., O’Malley, C. & Fraser, M. (2005). Designing the Spectator Experience. In: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems. CHI ’05. [Online]. 2005, New York, NY, USA: ACM, pp. 741–750. Available from: http://doi.acm.org/10.1145/1054972.1055074. [Accessed: 7 December 2015].
Rowe, R. (1993). Interactive Music Systems: Machine Listening and Composition. Cambridge MA: MIT Press.
Sanden, P. (2013). Liveness in Modern Music: Musicians, Technology, and the Perception of Performance. New York: Routledge.
Visi, F., Scramm, R. & Miranda, E. (2014). Use of Body Motion to Enhance Traditional Musical Instruments. In: Proceedings of NIME 2014. 2014, London, UK.
Winkler, T. (2001). Composing Interactive Music: Techniques and Ideas Using Max. New Ed. MIT Press.
Zappi, V., Mazzanti, D., Brogni, A. & Caldwell, D. (2011). Design and Evaluation of a Hybrid Reality Performance. In: Proceedings of the International Conference on New Interfaces for Musical Expression. [Online]. 2011, Oslo, Norway, pp. 355–360. Available from: http://www.nime.org/proceedings/2011/nime2011_355.pdf.