Depends also what you mean by "common 3 and 4 note chords."

If you don't count pitch inversions of a chord as the same type (e.g. if you want to be able to say that a major triad is different from a minor triad), there are 19 total 3-note chords in 12TET (to within respacing and transposition), and 43 4-note chords, all of which are used in plenty of music from the last 100 years. The best way to catalog those is by finding the most closely packed chromatic representation starting on 0 (which is sometimes called the "normal form"). Then a dominant seventh chord (e.g. G-B-D-F) is 0368 (B would be 0 in the G-B-D-F) example. 0123 is the chromatic cluster, 0235 is the dorian tetrachord, and so forth.

I do have an abstraction somewhere that takes a list of pitches by integer in any n-TET and outputs the normal form as a list, but I can't remember if I let the user choose whether or not to let chords related by pitch inversion to be the same or different type. I can dig it out if anyone is interested.

Matt

On Mon, Nov 2, 2015 at 1:13 AM, William Huston <williamahuston@gmail.com> wrote:
Wow, looks like just what I'm looking for.
Many thanks!


On Sun, Nov 1, 2015 at 11:46 PM, Joe Newlin <jtnewlin@gmail.com> wrote:
Check out chorddict-help.pd from rjlib: https://github.com/rjdj/rjlib/tree/master/rj

JN


On Sun, Nov 1, 2015 at 7:31 PM, William Huston <williamahuston@gmail.com> wrote:
>
> Before I reinvent the wheel, I'm wondering what people have done characterizing chord libraries?
>
> I'm looking for the root position constructions in terms of intervals for 3 and 4 note chords.
>
> I realize there are only a dozen or so which are mostly used, but just wondering what people have come up with.
>
> What would be really nice is to convert between things like:
>
> 1,3,5 -> "Major" -> 1,5,8
> 1,3b,5 -> "Minor" -> 1,4,8
> 1,4,5 -> "Sus4" -> 1,6,8
>
> I.e., Notes in scale,
> Common name, Interval map
>
> ... for all common 3 and 4 note chords. Like, given any one of those, can derive the others.
>
> Also would be nice given an interval map, be able to identify it as an inversion of a more basic chord, like:
>
> 1,5,8 -> Maj/root
> 1,4,9 -> Maj/1st inv
> 1,6,10 -> Maj/2nd inv
>
> Any pointers/ideas along these lines appreciated!
>
> Thanks
>
> --
> --
> May you, and all beings
> be happy and free from suffering :)
> -- ancient Buddhist Prayer (Metta)
>
>
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--
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May you, and all beings
be happy and free from suffering :)
-- ancient Buddhist Prayer (Metta)

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