generates repeatable sequences of 3 or 4 chords.
Strengths:
- Not limited to notes in the tonic scale
- Not limited to Ionian mode
- The results are usually viable
Weaknesses:
- Tested using only major and minor triads
- Won't do melodic or harmonic minor scales, or any modes derived therefrom,
but is easily adjusted to accommodate them
- If this generator is adjusted to produce longer sequences, the results
sound strange and tend to wander
I'm looking for help in improving this generator. Sorry it's so wordy. I used redundancy and precision to make it as clear as possible.
Code: Select all
0. Get a 6-sided die
1. Roll to choose the first chord in the sequence; we will call
this the Base Chord:
1 - I
2 - ii
3 - iii
4 - IV
5 - V
6 - vi
For example, in the key of C major these choices correspond
to C major, D minor, E minor, F major, G major, and A minor
respectively.
2. Roll to choose a Component of this first triad; we will call
this the Operating Voice:
1-2 - 1st
3-4 - 2nd
5-6 - 3rd
For example, the 1st, 2nd, and 3rd Components of the G
major chord are G, B, and D respectively.
3. Roll to choose the motion sequence that the Operating Voice
will undergo:
1-2 - ascending (up-up-up-up)
3-4 - descending (down-down-down-down)
5 - up-down-down-up
6 - down-up-up-down
4. Choose the number of semitones the Operating Voice will
move:
4a. If the current pitch of the Operating Voice is in our
scale (e.g. in the key of C major, if the pitch is C, D,
E, F, G, A, or B), roll:
1-3 - one semitone
4-6 - two semitones
Otherwise skip to step 4b.
4b. The Operating Voice moves one semitone.
Use the first member of our motion sequence to determine the
direction of motion.
5. Repeat step 4 using the new pitch to which the Operating
Voice has moved, and use the second member of our motion
sequence to determine the direction of motion.
6. If the pitch generated in step 5 is a Component of the Base
Chord, roll to see whether we dismiss the remainder of the
motion sequence and skip to step 9:
1-3 - Yes
4-6 - No
7. Repeat step 4 using the new pitch to which the Operating
Voice has moved, and use the third member of our motion
sequence to determine the direction of motion.
If the pitch generated in this step is a Component of the
Base Chord, skip to step 9.
8. The Operating Voice must move no more than two semitones
from the fourth to the fifth pitch in the sequence, and the
fifth pitch in the sequence must be a Component of the Base
Chord. Sometimes these requirements are incompatible with
the motion prescribed by the motion sequence and the
fourth pitch the Operating Voice has reached. In these
cases, either disregard the final member of the motion
sequence, or adjust the fourth pitch in the sequence by one
semitone, or both, as necessary.
=== Now we get down to generating chords ===
9. We already have the first chord.
10. We now generate the next chord. It might have 0, 1, or 2
Components in common with the previous chord (at least the
Operating Voice will have moved), and it might have 0, 1, 2,
or 3 Components in our scale. That makes 3x4=12
possibilities. Start at the top of the following list and
work your way down, determining whether or not any chords
exist that meet those requirements:
2 Components in common, 3 Components in our scale
1 Component in common, 3 Components in our scale
0 Components in common, 3 Components in our scale
2 Components in common, 2 Components in our scale
1 Components in common, 2 Components in our scale
2 Components in common, 1 Component in our scale
0 Components in common, 2 Components in our scale
2 Components in common, 0 Components in our scale
1 Component in common, 1 Component in our scale
0 Components in common, 1 Component in our scale
1 Component in common, 0 Components in our scale
0 Components in common, 0 Components in our scale
For example, let's say you're considering the item, "1
Component in common, 3 Components in our scale". Let's also
say our scale is C major, our current chord is C major, and
the Operating Voice moved from G to A. The new chord must
contain the Operating Voice, so the new chord contains A.
The new chord must have one Component in common with the
last. Now, there are six chords that contain A: A major, A
minor, F major, F-sharp minor, D major, and D minor. Of
these, two contain one Component in common with the chord C
major: A major and F major. Of these two, just one has all
three Components in the scale C major: F major.
If there is at least one valid choice, roll your die. If you
roll a 5 or a 6, reject this item, move to the next one in
the list, and try again.
If you exhaust the list without making a selection, go back
to the top and keep trying.
Sometimes there will be two or even three valid choices. In
these cases divide 1-6 up evenly and roll to make the
selection. If there are no choices, move to the next item on
the list and try again.
11. Repeat step 10 unless this is the final chord and the final
pitch of the Operating Voice sequence is a Component of the
Base Chord.
11a. If the sequence has 5 pitches, we've already generated
four chords. We're done and can disregard step 12.
Otherwise skip to 11b.
11b. Find all the chords that contain the Operating Voice's
pitch and whose other two Components differ from those
of the Base Chord by no more than one semitone. For
example, if the Base Chord is G major and the Operating
Voice's pitch is B, the chords you should be
considering are B minor, G major, and G-sharp minor.
Select one of these chords as the final chord by
rolling your die.
12. If we have generated only three chords and we assume a
four-bar phrase, we play one of our chords for two bars.
Roll to see which:
1-2 - 1st chord
3-4 - 2nd chord
5-6 - 3rd chord
Otherwise we're done.
