Örjan Sandred - Composer
2 (3)
(CAC cont.)


When composing with OMRC, it soon became obvious that it was necessary to include pitch in the calculation to make more precise musical sense.

In PWMC a composer can define relationships between pitch, rhythm and metric framework. It is for example possible to express traditional musical concepts such as:
  • notes on downbeats has to be consonant (relationship between pitch and the metric framework)
  • the largest allowed melodic interval at sixteenth notes is a major third (relationship between rhythm and pitch)
  • syncopations are not allowed over bar lines (relationship between rhythm and metric framework)
  • etc...

It is also possible to express less traditional concepts such as:
  • an energy peak in a melody should occur after 10 notes (typically the relationship between melodic shape and harmony)
  • 35 % of all durations should be sixteenth notes (statistical rules for overall control)
  • etc...

Any mix of these concepts is also possible.

PWMC was very well received. Several composers use the system. PWMC has been taught in courses at the Sibelius Academy in Helsinki, at the Harvard University in Cambridge as well as I have been teaching it myself in courses at the U of M.


The complex task of solving a musical Constraint Satisfaction Problem can be very demanding for a constraint solving system. Typically, when a system is trying to generate a polyphonic score that satisfy user-defined relations between rhythms and pitches over several voices, it gets stuck. The intricate network of dependencies that exist in a score makes it hard to develop a good

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