Computational Creativity and Music - Computational Creativity Research: Towards Creative Machines - page 313

Fig. 15.8 Computer-created
extrapolations of a chromatic
pitch from Fig. 15.7

(a)

5 3 r

3 r 5

r 7 3

- 1 1
- 2 0
0 - 1

M Mm 4

M 6

2

(b) 5 3 r

3 r 5

r 7 3

- 1 1
- 2 0
0 - 1

M

Mm 4

M 6

2

fifth of a major triad it can correctly move downward a minor second to the third of a
Mm seventh chord given the roles of the other voices conform as well. The alto and
tenor voices can be stated in exactly the same ways with the resultant rule confirmed
by the last three chords in Fig. 15.6 b.
With this rule in mind, a computer program can and will—without instruction to
the contrary—use it to create both of the examples in Fig. 15.8 .
These two examples follow exactly the rule derived from the voice leading in the
database, but in doing so create chromatic pitches not present in those two phrases
as exemplified in the new phrase shown in Fig. 15.9 .

Fig. 15.9 Output using materials from Fig. 15.6 and rules shown in Fig. 15.7