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Minimalism

A minimalist canon at augmentation, for piano.

Programs

canon.pl
This runs from Perl, via system:
```
 perl amini.pl @ARGV
 perl yabmini.pl
 perl cmini.pl
```
creating two complete scores with the corresponding midi files.
- The program uses a parameter list, of the form
  rand_2345 size_20
  This means: initialize random generator with 2345, and make 20 motifs. The parameters are optional; they are also used in naming the score files:
  sc2345-20
  nocoda2345-20,
  in this case. There will also be midi files: sc2345-20.mid and nocoda2345-20.mid .
  The motifs, each repeated several times times form the basic strand.
- The 1st voice plays twice the basic strand, with a break before the repetition.
- The 2nd voice plays the basic strand once, one octave lower in augmentation (twice as slow). It enters after a random time, making an unpredictable canon. One of the voices usually may play alone at the end of the canon, but for most of the piece the two voices play together.
- The first motif is generated (at random) as one of:
  1. part of a scale (major or minor)
  2. arpeggio, i.e. tones following each other at intervals of 3 or 4 semitones (at random), all in the same direction, up or down.
  3. equally spaced, i.e. tones following each other at intervals of n semitones, all in the same direction, up or down. The number n is picked at random, from the set 1,2,3,4,5,7 (no tritones).
- Each subsequent motif is a small change of the previous motif.
  - cancrizans: the motif played backwards
  - add one accident (flat or sharp) to one note in the motif
  - transpose the motif, by 1,2 or 3 semitones, up or down
  - add one note to the motif (should be consistent with its type: scale, arpeggio, equally spaced). The note may be added at either end.
  - add a rest to the motif, before it , after it or between any 2 notes
  - delete one note from the motif, at any position
  - fold two note in a chord, only if the chord is a minor/major third/sixth. (With a big grain of salt: either the motif is an arpeggio, or the distance from the first to last note in the chord is 3,4,8,9 semitones. The program would, for instance, fold C#,E,F or C,E,G# )
  - mix the notes in the motif (play them all, in random order). This, of course, destroys type: the motif, usually, no longer is equally spaced, a scale, or an arpeggio. In addition, the chords made by folding afterwards may be dissonant. Therefore, mixing is assigned a smaller probability than the other modifications. In addition, with high probability, the reordering swaps only one pair of contiguous notes.
- Up to now we only discussed the notes in the motifs, not their durations. The motifs get assigned to simple rhythms in 3/4 or 4/4, picked from given lists. The whole piece stays in either 3/4 or 4/4. This makes for easy listening (typical minimalism) but may be not truly interesting.
- DETAILS
  - amini
    This creates the motifs, and produces the files nocodaRAND-SIZE and nocodaRAND-SIZE.mid. As their names implies, there is no coda, and the voices proceed independently to completion. However, the result may be interesting because there is built in randomness: every time you run
    midi nocodarand-size
    you get a different nocodarand-size.mid with different dynamics and another entry time for voice 2.
    The program also writes an intermediate file minipas.txt, to be used by the other programs yabmini and cmini to create a coda to conclude the piece. This file is just a list of shorties in 8 voices. The shorty is the smallest duration in the piece, typically 1/16 or 1/8, and all other durations are multiples of it. E.g., if the shorty is 1/16, a quarter note will be emitted in 4 records in minipas.txt .
    Up to now there was no consideration of harmony, the two voices advance in canon, although each voice may have folds. This is why up to 8 voices will sound.
  - yabmini
    Here we consider the harmony between the (up to) eight voices, to discover a cadence near the end, on which to end the piece. This is done by gathering chords and checking versus a big list of acceptable cadences. If none is found, yabmini exits and the driver program canon.pl will call cmini, to supply a coda otherwise.
    If a cadence is found, then the durations of the notes around it are modified, to emphasize it. A few preceding chords are also reset to belong to the scale of the final cadence. The coda is attached to the previous canon, with a suitable rallentando, and the score is written, and processed to a midi file.
    If there is a cadence, the canon is incomplete – voice 1 does not play the basic strand twice, and voice 2 does not play all the basic strand, only 'most of' that.
  - cmini
    This is called only if yabmini fails, i.e. cannot discover a cadence. Then cmini looks for a long sequence of shorties, towards the end, all belonging to some scale (tonality) . It then supplies a final close in that scale, with the same procedure as above:
    - duration adjustment
    - rallentando
    - incomplete canon
    The resulting files will be named tyrand-size and tyrand-size.mid – ty stands for tonality.
Alas! the whole setup is mostly overkill, the codas don't sound natural or especially effective. The version without coda is much simpler and cleaner, but it does sound incomplete. A non-harmonic, somehow organic, coda?
- mini.pl
  Builds the complete score, on a file par.txt. If you want, munge it, or just:
```
 copy par.txt somename
 midi somename
 
```
  That makes the midi file somename.mid, that you can listen to. There is random dependence on time, so if you say
```
 
 midi somename
 
```
  later, you get a new sound file: the same strands used in counterpoint, but voice 2 enters at a different time, and the dynamics are different all over.
  TO DO : it should end on some kind of coda. ( Done: see canon.pl above )
- varep.pl
  The same as above, but the motifs are repeated 2,3,4 or 5 times at random, and the dynamics are a little different, over a larger range.

canon.pl

DETAILS

amini

yabmini

cmini

mini.pl

varep.pl