Denis Lorrain

Construction 073

Tre cuori, sette vite

Algorithmic composition for MIDI piano

(2024, total duration: *ca.* 17'30")

Programme Note

   The seven short pieces of this Construction range in duration from 49" to 3'30". They can be heard as *seven lives* individually unfolding in succession. The *three hearts* mentioned in the title refer to the three algorithms which symbolically breathe life into the pieces. These algorithms are the exclusive origin of all their musical material. I have already used them in one or more of my previous Constructions.

1. Harmonic, producing chords encompassing the piano range, either legato or staccato. This algorithm is based on hexachords comprising all intervals from one to five semitones (*all-interval hexachords*, algorithm of Jan Vandenheede). A couple of hexachords forms a dodecaphonic series, itself varied and multiplied by means of generalised axial symmetry operations in a circular representation of the chromatic space. Beyond their constituent notes, this algorithm attempts to optimise the *position* of the chords — i.e. the distribution of their notes in the instrument's range. The interventions of this algorithm, in several of the seven pieces, are obvious on hearing.

2. Melodic, which is based on a simplified liana-like model of plant growth, and whose settings allow a wide variety of results.

   2.1. On the one hand, this algorithm can produce more or less slow, haunting melodies, with frequent repeated notes, initially in a restricted register, then gradually widened. A line of this type can be heard at the end of the first piece (in octaves in the high register). In the second piece, a single slow melody is used within the framework of classical contrapuntal formalisms (original, reversed, retrograde, reversed retrograde). In my view, this piece conveys a calm and appeased impression. From the beginning of the third piece, such lines are gradually accumulated, accelerating until they reach the extreme saturation described below in 2.2. In the fourth piece, several such lines are heard in counterpoint, before and after a staccato chords interlude. In the sixth piece, such a high-pitched and very slow line hovers above the chord resonances.

   2.2. On the other hand, at the extreme, this algorithm can also create the most extravagant flights of rapid, disordered lines across an entire register. Such exuberant lines can be heard in the third piece, as well as in the fifth and seventh.

3. Trills or batteries of two notes, used to weave links between events, or to create supporting backgrounds.

   The durations of the seven pieces are respectively:

   I — 3'11"

  II — 3'29"

III — 2'05"

IV — 2'29"

  V — 2'47"

 VI — 2'22"

VII — 0'49"

DLO

Cologne

January 2025