Moment musical

Trio for piano and two of : clarinet, flute, oboe, trumpet, violin, cello or bassoon .

The instruction:

perl  driver.pl   rand_345     tritone_1     noise_min    

will produce a score named  mom345  and the corresponding midi file  mom345.mid.

The program driver.pl executes:

		perl iizum.pl @ARGV > res1.txt 
		perl i4zum.pl > res2.txt 
		copy hdr-momen.txt + momen.txt + res1.txt  mom$ID 
		midi mom$ID
	 

• parses the parameter list

  rand_seed     tritone_1     noise_noise    

  All the parameters are optional. Their interpretation is as follows:

  rand_seed

  The number seed is used to initialize the random numbers generator. This is also the variable $ID used in the driver.

  tritone_1

  if specified, the basic subjects do not contain tritones

  noise_noise

  All the possible chords are assigned a grade, the higher for the more dissonant. If omitted, use twelve tone scale, with the all triads and sevenths considered consonanat. Other values for noise may be :

  maj

  use major scale, with the scale triads and sevenths considered consonanat

  min

  use minor scale, with the scale triads and sevenths considered consonanat
  

• reads the data files

  noise

  maj.txt,  min.txt,  any.txt

  rhythm

  rhyspli.txt

• sets the basic structure

  this consists of

  • two independent melodic voices, each built from a color (random notes from the scale specified, with the tritone constraint) and talea (read at random from the rhythm file), repeated 2 or 3 times
  • a harmonic rhythm, which specifies change of harmony whenever one of the melodic voices changes pitch
  • tension, requiring a definite amount of dissonance for the harmonization.
    For instance, assume the notes in the two voices are C,E. If low tension is required they may be harmonized with G,C and if high tension is required they will be harmonized with D♭,E♭.
    Tension is computed by the program so it will start and end low (consonant harmony) with three random peaks during the piece.

• writes the intermediate files

  parameters

  parm.txt

  pass file

  pasa.txt, containing the two melodic strains and the tension.

The program   i4zum.pl :

• reads the data files

  noise

  maj.txt,  min.txt,  any.txt

  parameters

  parm.txt

  pass file

  pasa.txt, containing the two melodic strains and the tension.

• builds the harmonization

  Adds three voices to the 2 voices read from pasa.txt . If the resulting chord is above the required tension – i.e. too dissonant, softens it using cambiata and trills.
  The five voices ranges are 2 basses, 2 sopranos and one tenor.

• analyzes the resulting score to find a cadence

  If no cadence is found, the program fails and the driver increases seed , then restarts the procedure with iizum.pl.

• writes the score

  This score ends with the cadence found above, and has the generic name momen.txt . The driver then combines the various output files into the final score momseed.