The ‘Tone Field’ project explores the design of new, spatial based musical composition and performance systems, using spatial Ambisonic sound modelling software and a 12-channel speaker system. The composer arranges constantly sounding tones spatially on a grid, deciding for each tone the pitch and location. The Ambisonic software then models a virtual spatial soundscape, in which each tone occupies a specific location. The musician then performs the piece by deciding in real-time the pathway a virtual listener takes through the grid. As the virtual listener gets closer to a tone, it becomes louder. When in the vicinity of multiple tones, a musical chord may be perceived, depending on the location of the virtual listener in respect to the tones. Performances of the same composition are different every time, due to a different path and speed of movement being chosen each time.