Rhythmic Canon

A contrapuntal technique which juxtaposes a rhythmic phrase (a voice) with subsequent copies of itself, where instantiations are separated by a given duration-value. Voices can also be combined while different instantiations are presented in different time-scales (tempo canon). In tempo-canons, the ratio between the involved time-scales determines if the tempo-canon is harmonic (between integers, as 1:2) or inharmonic (irrational ratios, as 24/25). American composer Conlon Nancarrow (1912-97) is well known for his use of irrational tempo-canons, as in Study 43 for mechanical piano.