acceleration canon
English work
Definition
A canon in which one or more voices continuously change speed — accelerating or decelerating — rather than maintaining a fixed tempo throughout. First explored by Nancarrow in Study No. 8 and brought to its most famous expression in Study No. 21 (Canon X).
Interpretive Guidance
In an acceleration canon, the convergence point is not a fixed structural anchor but a moving target: the faster-accelerating voice 'catches up' to the decelerating voice at a point determined by their rate of change, not their initial speeds. In Canon X, one voice starts fast and decelerates while the other starts slow and accelerates — they cross in the middle.