Download * Interdisciplinary Background Notes with clearly longer note values

* Interdisciplinary Background
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Notes with clearly longer note values (IOIs) than their preceding note(s) are
accented. Music perception research supports such durational accents.
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The importance and simplicity of this musical feature makes it a good
candidate for computer-aided composition. Various approaches to rhythm
generation have been proposed, but accents have not been modelled before
(to the best of our knowledge).
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Constraint programming has often be used for modelling music theories,
including rhythm, because declarative constraints are highly suitable for
implementing music theory rules.
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* Contribution
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We propose a computational model of rhythm for computer-aided
composition based on music theory insights about durational accents. The
model controls the temporal position of durational accents. It is
implemented by constraints, and can therefore be combined with other
constraints affecting the rhythm (besides constraints on melody, harmony,
etc.).
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* Method
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We use a music representation, where compositional parameters (e.g., note
values and pitches) are represented by variables, whose values are found by
a constraint solver. Durational accents are modelled by a custom reified
constraint - a constraint whose truth value is constrainable. Other
constraints control whether or not this accent constraint holds for certain
metric positions, or more generally, temporal positions.
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* Examples
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The model is demonstrated by several examples. Durational accents
emphasise regular metric accents (as often found in common practise
music), and irregular accent patterns in a clave rhythm. In a more complex
example, accents of the harmonic rhythm are controlled, together with
further constraints on the actual voices.
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* Impact
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With our model, the algorithmic composer flexibly shapes accents in
various rhythmic contexts. The resulting music confirms the effectiveness
of durational accents, and thus helps us to better understand rhythmic
accents. !
* Interdisciplinary Nature
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This research uses concepts from music theory, models them with
computer science methods, and applies them to composition.