Real-Time Adaptive Tunings Using Max
William A. Sethares · Journal of New Music Research · 2002
Adaptive tunings adjust the pitches of notes in a musical performance based on some criterion such as fidelity to a desired set of intervals, or minimization of a measure of dissonance (or maximization of consonance) of the currently sounding notes. This paper presents a real-time implementation of an adaptive tuning algorithm that changes the pitches of notes in a musical performance so as to minimize sensory dissonance. The algorithm operates in real time, is responsive to the notes played, and can be readily tailored to the timbre (or spectrum) of the sound. One issue with adaptive retunings is that the pitches may wander; the pitch of a “C” note one time may differ from the pitch of the “same C” at another time. This is addressed in Adaptun by the use of a context, an (inaudible) collection of partials that are used in the calculation of dissonance within the algorithm, but that are not themselves adapted or sounded. Several sound examples are presented that highlight both strengths and weaknesses of the implementation. The program Adaptun is written in the Max language and is available for download.