Computers have been assisting in recording, sound synthesis and other fields of music production for quite some time. The actual performance of music continues to be an area in which human players are chosen over computer performers. Musical performance is an area in which personalization is more important than consistency. Human players play with each other, reacting to phrases and ideas created by the players that they are playing with. Computer performers lack the ability to react to the changes in the performance that humans perceive naturally, giving the human players an advantage over the computer performers. This thesis creates a framework for describing unique musical performers that can play along in realtime with human players. FrTime, a reactive programming language, is used to constantly create new musical phrases. Musical phrases are constructed by unique user programmed performers and by chord changes that the framework provides. The reactive language creates multiple musical phrases for each point in time. A simple module which chooses musical phrases to be performed at the time of performance is created.

Since the introduction of the Walkman in the 1980s, an increasing amount of people are using mobile music devices in our urban environments. The research on the sociological aspects of this phenomenon has become known as the ‘iPod culture’. It describes people aestheticising these noisy urban environments by replacing them with mobile music listening, which presents obvious benefits regarding personal entertainment and wellbeing. However, some studies have revealed several cases of users experiencing social isolation as a consequence of using mobile music devices. Therefore, this study explores the problem of designing a user experience that can provide the appealing qualities of mobile music listening while simultaneously enabling spatial and social awareness of the urban environment. The study explores this problem by applying a methodology inspired by research through design, involving an iterative design process centred around the design of a mobile reactive music prototype application, which was eventually named Reactiscape. To validate and evaluate the success of the prototype design, different stakeholders have been involved throughout the entire design process. The results show that the users experienced a stronger connection to the urban soundscape when using Reactiscape, while still maintaining a musically appealing user experience. In a broader sense, these results indicate that novel mobile technology design has every opportunity to increase real world social interaction, rather than being a source of social isolation.