question about harmonizing synthetic scales

[dermichl]

how do you harmonize synthetic scales that lack some thirds for constructing triads?

eg a scale like : a - b flat - d - e flat - f flat - g

[Chainsaw Calligraphy]

The easiest way is simply to use chords that aren't derived from the scale. The other approach is to use non-tertian harmony; i.e chords built on seconds, fourths, fifths or mixed intervals. If you're interested in 20th century and contemporary classical, film scores or more avant-garde sub genres, non-tertian harmony is definitely the way to go.

[dermichl]

good call - seems to be an appropriate tool to use chords derived of forths when using constructed scales!

[jancivil]

You might want to get away from chords thinking with something like that and start thinking in terms of other lines that complement, and find felicitous vertical combinations there.

[dermichl]

You might want to get away from chords thinking with something like that and start thinking in terms of other lines that complement, and find felicitous vertical combinations there.

so this would be a "call for counterpoint", wouldn't it?

[jancivil]

I see a spelling 'D Eb Fb' [rather than 'E'] and think Eb is being circled with the two chrom. neighbors; I also see D as a plateau in addition to A; so my instinct is for fluidity.
IE: it looks more like modal quality of line, like the particular construction is significant so my instinct is to allow for transparency (as opposed to blocks).

[MadBrain]

how do you harmonize synthetic scales that lack some thirds for constructing triads?

Same as harmonizing a blues scale: use harmony from a similar diatonic scale.

eg a scale like : a - b flat - d - e flat - f flat - g

Then harmonize it like you would harmonize a melody using the phrygian scale (A Bb C D E F G). Whenever Eb appears, either treat it like an ornamental accidental (just like how you'd treat the Eb in the A minor blues scale A C D Eb E G), or figure out a chord that puts this note in an interesting light and works well with neighboring notes (examples: B7 if you don't have Bb nearby, Bb9sus4 if you don't have A nearby).

[Musicologo]

Why not going for a mix solution of "counterpoint" and "chords" by using an algorithm?

"A chord is a sequence of note-yes-note-not"

A-Bb-D-Eb-Fb-G

I can spot-
A-D-Fb
Bb-Eb-G
D-Fb-A
Eb-G-Bb
Fb-A-D
G-Bb-Eb

So basically with 2 chords you can harmonize the entire scale.

Or you can come up with some other "rule" like "Make up chords equal to the diatonic scales but rounding up to the nearest note in its absence"...

That would imply

A-C-Eb -> Since there's no "C" you use A-D-Eb (or A-Bb-Eb)
Bb-D-Fb
D-Fb-A
Eb-G-Bb
Fb-A-D
G-Bb-D

As long as you have a set of "consistent" rules anything may go.