Obsidian for Cor Anglais, Clarinet in A and Bassoon Norman Skipp 2011
Obsidian is a naturally occurring volcanic glass often dark in colour varying from dark green to black. Developing ideas further from a miniature for clarinet quartet, Obsidian explores sonority and movement within sound. Using blocks of colour and largely aleatoric sections, the form is largely static drawing the listener in to the subtle changes in timbre. The piece uses a proportional notation, with the score divided into 48 sections of relatively similar duration. This is to give the performer an idea of approximate relative duration, and to allow the performers to listen and feel the appropriate speed and tempo of each sound object. This sense of listening and responding is influenced by work within free improvisation and live electronics.