Greetings fellow humans,
I’ve finally made it to a beach where I can relax and go over some recordings and work from the past month or so. I’ve been working with my 15-tone guitar, recording improvisations each day with the goal of learning in depth the sounds and patterns of this instrument. This was the same method I used for recording my two solo piano albums The Moon (https://noahdeanjordan.bandcamp.com/album/the-moon), in 18-edo or 1/3 tone (Sonido 13), and The Devil (https://noahdeanjordan.bandcamp.com/album/the-devil). I have been releasing one of the improvisations each week on my new Patreon page (https://www.patreon.com/noahdeanjordan), which you should definitely check out if you are interested in this progress. There are also live videos I am releasing from places where I can record audio and video, so far this has been in Swakopmund, Namibia,, Klein Brak Rivier, South Africa,, Joza, South Africa,, and most recently: Maputo, Mozambique where I recorded the Bad Canada song: SWOUP.
Two days ago I was at the Timbila Music Festival in Zavala, Mozambique. I was able to spend the day watching great performances of music and dance with abundant cervejas and the most delicious pork skewers.
The timbila is a mallet percussion instrument, similar to the xylophone or marimba but with a very unique and wonderful tuning. The tuning is heptatonic (7 tones per octave) and they are somewhat evenly spaced, the first steps actually being very close to the steps of my 15-tone guitar (160¢). There are 3 sizes of timbila, with the lowest generally having only 3 or 4 keys. The timbila music is very very lively but with a soft sound of the mallets on the wood. There are almost always many layers of rhythms and the instruments blend together to make a hypnotic texture of layers upon layers of melodies and rhythms.
I believe that this tuning, being a near 7-equal tuning, is well suited for this type of music. Because of the many layers of the music and the symmetries, it creates a diatonic-type texture that is familiar, but with a neutral second as the interval that is characteristic to the music and heard by the musicians as quite fundamental. In a sense this is a music characterized by the 11th harmonic. The perpetual beating I believe helps to push forth the energy of the music, and allows all the instruments to blend together to create a very rich-textured harmony but with simple components, allowing melodies to flow in and other of each other, with every player playing a unique part which was a piece of the whole, the music completely acoustic but with great volume when desired. This festival occurs every year in August in Zavala, and has for the past 23 years.
It is important to consider attributes of tuning in different traditions of music, as this same effect could not be obtained by any subset of 12-tone equal temperament, or with any just intonation 5-limit diatonic scale.
Some questions I will put forth about this:
What is the function of the 11th harmonic?
Can 7-edo be legitimately described as a tuning representing the 11th harmonic?
In my opinion, 5-edo is in the same way a tuning representing the 7th harmonic. Can the 720¢ fifth be described in some what as a fifth of the 7th harmonic? Even though it does not actually approximate this harmonic in any way.
Stay tuned for the next part where I will speak about the Blackwood  symmetrical scales in 15-edo (and other tunings)