Abstract

Sonic Pi is a piece of software combining musical concepts, programming techniques and sophisticated theory on keeping time. This talk is aimed as an introduction to the features and underlying theory. I shall first give some background to what Sonic Pi is and why it was created, as well as demonstrate some of its flagship features. In particular, there will be live coding in Sonic Pi, example coded compositions and a demonstration of how you can recreate Pachelbel’s Canon in D with just three audio samples! Afterwards, we shall focus on the underlying theory that allows it to function as a musical device. We shall examine the key idea of its temporal semantics, namely the separation between virtual time and actual time, which enables the indefinite keeping of a constant rhythm, on a timesharing system with interrupts. To conclude, we state and prove the Time Safety lemma, which is the correctness result for these temporal semantics.