[PD] a composition of mine made with pd

Charles Henry czhenry at gmail.com
Tue Jul 17 01:59:09 CEST 2007

> http://megalego.free.fr/pd/scoregame/polyrytharm.pd
> For adding spice I've also divided the octave by the number of notes in
> the polyrythm.

That's really interesting, and I love the graphical output.  It's very
whimsical, having the animated notes that go around in circles on the

>   I've been particulary interested by your microtonal guitar, and I'm
> curious if the player is able to make good sounding chords with it.
>   Also it's possible to play microtonal scales with an usual guitar,
> with  just tuning strings differently, for example by lowering the G
> string about 1/4 tone, then with the ratio between the G string and the
> B string, it's possible to play 24 notes scales, not in an easy way, I
> admit.

The guitar is not that hard to play, after all.  Diatonic scales line
up very well in 19-tet, but there's extra notes in between.
In 12-tet you have a diatonic scale as follows:
In 19-tet, you have
so, there are notes of the chromatic scale as follows:

Chords based on diatonic scale line up very well in 19-tet.  I can
play nearly anything on the "microtonal" 19-tet scale that I could
also play in 12-tet.  It's advantage is in chromatic voice variation,
since there are extra notes to use, and some intervals become evenly
Example, a perfect 4th is 8/19th of an octave; it's divisible by 2,4, or 8
On the other hand, 19 is a prime number, so none of the intervals
evenly divide the octave any more.  So, diminished/augmented chords
are out, despite having more variations that all sound like dim or aug
chords with small variations

At the moment, I have tuned the guitar from C to E, so that the
frequency ratio between any two strings is an odd harmonic ratio.

it goes:
C, A, D#, G, B#, E  (as numbers: 0,14,23,30,37,44) and the ratios
between strings are:
5/3 ,  7/5 , 9/7 , 9/7 , 9/7

and I have no idea what to do with it.  I work on it sometimes, but I
don't know how it's actually useful for anything.


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