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by mhauru 1900 days ago
At any one time, yes, there's always a root tone and the tuning system is generated with respect to that root. Such is the nature of pure harmony. This is one of the reasons (I would say the main reason) why equal temperament tuning rather than just intonation is dominant in our culture.

You can change the frequency of the root tone in the settings though (gear icon, top right). You have to specify it in Hz which is a bit inconvenient, sorry about that. To compute the frequency in Hz for any tone on the usual piano keys, compute 2^(n/12) * 440, where n is the number of semitones above (n>0) or below (n<0) the mid A that you want the root tone to be. If that's not clear, let me know and I can give you list of frequencies for various tones.
2 comments
mwcampbell 1900 days ago
> At any one time, yes,

And changing keys mid-song is kind of passé, at least in popular music, isn't it? At least, the common practice of modulating up a key for a repeat chorus is a cliché.

Edit: Then again, just now I was listening to a song that, while it doesn't have the clichéd upward key change, does move between two major keys. I'm guessing this song, as written, couldn't be played in just intonation. https://music.youtube.com/watch?v=ElsdmXU8dUw And yes, I know I have questionable taste in music.

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genericguy 1900 days ago
But you can't even play a chord progression in tune without changing the root tone.

Not dissing this, it's a cool experiment and I like the visualization, but there's a reason strict just intonation hasn't been used for 500 years.

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mhauru 1900 days ago
Not sure I see what you mean. Here's the infamous I – V – VI – III – IV – I – IV – V progression from Canon in D in just intonation, with square brackets marking tones that make up a chord (invert the chords to your taste): [1/1 5/4 3/2] – [3/2 15/8 9/8] – [5/3 1/1 5/4] – [5/4 3/2 15/8] – [4/3 5/3 1/1] – [1/1 5/4 3/2] – [4/3 5/3 1/1] – [3/2 15/8 9/8]

Of course, you can't do this for every progression you might enjoy playing, but as an example this one works out quite nicely, with no serious harmonic ambiguity or conflict.

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