I’ve been exploring with the Partch 43-tone scale and one of the things I’ve been curious about is how one might go about navigating a scale that has so many degrees.

My first step has been to add a colour scheme to the overlay that I created for the Sensel Morph, based on the colours that Partch himself used on his Chromolodeons.

With that the symmetry of the scale becomes immediately apparent. The coloured hexagons are the ratios from the 11-limit tonality diamond that Partch has at the core of his scale, and the grey hexagons are the additional tones that he added in-between those core ratios as a way of filling in some of the wider gaps, and making a wider range of harmonies possible.

So the ratios in the top right hand quadrant will be mirrored in the bottom left, and vice versa. To demonstrate: a pure fifth 1/1:3/2 will correspondingly give me a pure fifth here 2/1:4/3. I can also go to another degree of the scale, 16/15:8/5 will corresponding give me a pure fifth here 15/8:5/4. You can also do that on other degrees of the scale 81/80:32/21, but here you won’t get a pure fifth, you can hear some beating, and the same thing here 21/20:11/7, 33/32:14/9 slightly faster beating. But if I go back to one of the pure fifths 1/1:3/2 and add a third 5/4 you get a nice pure major triad, or minor 1/1:6/5:3/2. There are also two ‘alternative’ degrees of the scale, e.g. here 10/9:4/3 I get a minor third, but if I take this one 11/10:4/3 it’s no longer in tune, but what it does give me is a purely tuned major second (10/9), and correspondingly 20/11:18/11, I get the pure major second over there.

So that’s a little start in how one might go about navigating the 43 tones of the scale. I find the the symmetries are really useful in reducing the amount of information that one has to deal with.

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Partch 43-tone overlay for the SenselMorph

I added colours to my overlay for the #SenselMorph after taking a look at the colours that Partch himself added to his Chromelodeon organs. It makes all those ratios a little easier to navigate. The overlay and map can be downloaded from the Sensel forum:

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I’ve recently experimented with the Partch 43-tone scale, here in the Wilsonic app, sending it over to the Audiokit SynthOne in order to play it with those sounds using the overlay I created for the Sensel Morph, and I was curious to try something similar with the Audio Damage Continua synth. Unfortunately there’s no easy way to send the tuning directly from Wilsonic to Continua but it is possible to go over to, to the scale workshop there, where the Partch scale is available as one of the presets that can be loaded.

I’ve set the base MIDI note to 60 and the base frequency to 261.626 Hz, which corresponds to an equally tempered Middle C. That can then be exported as a .tun file which can in turn be imported into Continua. And voila, the Partch scale in Continua.

The nice thing about Continua is that it offers MIDI MPE which means that you can alter the pitch the timbre of each note independently of the others. So, for example, I can alter the waveform of the 5th, or its pitch, or the root.

And so suddenly, in addition to the scale, you have a whole range of expressive possibilities at your fingertips.

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Harry Partch’s 43-tone scale in @Marcus_W_Hobbs’ wonderful Wilsonic app → @AudioKitPro SynthOne, with the @Senselinc #SenselMorph

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