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The Basic Model: construct a single tonal melody

Assumptions

This model is based on the following assumptions:
  1. A tonal melody is constructed within the 2-dimensional space of time and pitch which are respectively configured by key and meter.
  2. A tonal melody is constructed on top of a harmonic progression [implying that melody and harmony are independent at least to some extent. This is maybe too limiting a view: according to Schenker tonal melodies arise from bass motion and thus are intrinsically related to the harmony]
  1. Tonal harmonies are fundamentally triadic (Brown, 1989)
  2. The harmonic progression is hierarchically organized, i.e., consists of structural chords and non-structural chords (prolongations)
  3. The basic harmonic progression (the harmonic skeleton, if you like) is said either to consist of
  1.  the sections Tonic – Predominant – Dominant – Tonic  (Predominant chords are: ii, ii, IV, vi, vii.) or
  2. Opening section (tonic prolongation) – Closing section (dynamic harmony + Final Cadence). This is Sutcliffe’s model. More
  1. As a consequence the chord tones (the tones belonging to the current harmony) form the basis of a tonal melody which can be supplemented by non-chord tones that form connections between the chord tones. A classification of non-chord tones can be found here.
It will soon become clear that these concepts are insufficient to produce acceptable tonal melodies. The reasons for this are further explored in the other models.

Construction

1. The construction of a tonal melody

The interface comprises a number of construction buttons that may have a little ‘light’ on their left. If a button is disabled it has no light, and the button cannot be pushed, indicating that first other aspects of the melody have to be generated. By pushing the buttons with a red or green ‘light’ an aspect of the melody will be created and the result shown on the score paper. Before pushing a button you can adjust the associated parameters, shown in red, if you move the mouse over the button. A melody is build in the following steps:
  1. Set Key and Meter. Parameters determine the tonal context of the melody
  2. Set Rhythm. Parameters: Syncopation, rhythmical density, and rhythmical constraints (whether or not some or all bars have the same rhythm). More
  3. Set the Gap at the end of the melody. Parameter: Gap size
  4. Set Harmony. Parameter: progression type
  5. Set Contour. Contour is chosen randomly. Parameters: Tone repetition and Contourconstraint: determines whether the bars having the same rhythm should also have the same contour.
  6. Set Chord Tones. Selects which notes will become Chord tones and actually determines the pitches of those tones. Parameters: percentage non-chord tones; percentage accented non-chord tones
  7. Set NonChord Tones. Parameter: Chromatic tones.
By varying the different parameters the user can explore their effects on the resulting melody.

The order of constructing the different aspects is as shown in the figure below. This order is automatically enforced in the interface of Model 1.

OrderBasicModel

ConstructionSingelMelody.graffle

Note: you can push the enabled buttons as often as you like and look at and listen to the results.

2. The construction of a non-tonal melody

The possibility to construct (partial) non-tonal melodies has mainly been added for demonstration purposes: it is instructive to examine what happens if one or both of the underlying constraints underlying a tonal melody, key and meter, is removed.
A ‘non-metered’ melody can be constructed by selecting “No” in the MeterSelector.
A ‘non-key’ melody cam be constructed by selecting ‘No Key” in the KeySelector. If you do this a melody is constructed in 4 steps:
  1. Set Key and Meter. This merely creates a new melody object.
  2. Set Rhythm. More
  3. Set the Gap at the end of the melody.
  4. Set Pitches. Pitches are randomly selected from either a diatonic or chromatic alphabet, or based on "Brownian movement". More

References

Brown, M.G. (1989). A rational reconstruction of Schenkerian Theory. Thesis Cornell University.
Sutcliffe’s theory of harmonic phrase structure can be found at http://www.harmony.org.uk/

(For a complete list of references click here)

(BasicModel.html. Last update: 9.11.2010)
Created with SeaMonkey
© D.J. Povel. 2007

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