Market-Based Control in Interactive Music Environments

The paper presents the interactive music system SoloJam, which allows a group of participants with little or no musical training to effectively play together in a "band-like" setting. It allows the participants to take turns playing solos made up of rhythmic pattern sequences. We specify the issue at hand for enabling such participation as being the requirement of decentralised coherent circulation of playing solos. Satisfying this requirement necessitates some form of intelligence within the devices used for participation, with each participant being associated with their respective enabling device. Markets consist of buyers and sellers, which interact with each other in order to trade commodities. Based on this idea, we let devices enable buying and selling, more precisely bidding and auctioneering, and assist participants trade in musical terms. Consequentially, the intelligence in the devices is modelled as their ability to help participants trade solo playing responsibilities with each other. This requires them to possess the capability of assessing the utility of the associated participant's deservedness of being the soloist, the capability of holding auctions on behalf of the participant, and of enabling the participant bid within these auctions. We show that holding auctions and helping bid within them enables decentralisation of co-ordinating solo circulation, and a properly designed utility function enables coherence in the musical output. The market-based approach helps achieve decentralised coherent circulation with artificial agents simulating human participants. The effectiveness of the approach is further supported when human users participate. As a result, the approach is shown to be effective at enabling participants with little or no musical training to play together in SoloJam.