Kyrie juxtaposes two separate musical layers, and requires them to interact the first layer (for vocalists) is based on William Byrd’s Kyrie from the mass for 4 voices in this layer I have fragmented Byrd’s music and constructed small cells which each singer repeats numerous times in their own rhythm (based on their heartbeat) I removed most scalar material and placed it in two semi-­improvisatory solo parts the second layer is for an open instrumentation and consists of a set of drones: a fixed drone of an open fifth a moving drone based on the same fifth and a series of bass notes that contextualize the moving drones in relation to the harmonic series singers in the first layer must constantly shift their perception of where the tonal centre is due to the moving drones players or singers in the second layer must not listen to the first layer, and instead produce accurate drones and bass notes however possible (possible solutions discussed in further pages)