This paper presents a method for using a runner’s pace for real-time control of the time-scaling functionality of a phase vocoder, resulting in the automated synchronization of an audio track tempo to the generated control signal. The increase in usage of portable music players during exercise has given rise to the development of new personal exercise aids, most notably the Nike+iPod system, which relies upon embedded sensor technologies to provide kinematic workout statistics. There are also automated playlist selection
systems that select songs based upon the measured step frequency of a runner. While the proposed system also uses the pace of a runner, this information is instead used to manipulate audio track tempo. The result is an adaptive audio accompaniment that increases the cohesive interaction between a runner and playback device.
Keywords: NIME, synchronization, exercise, time-scaling.