Hi folks,
I wrote a little online tool which allows you to hear what different tuning systems sound like.
https://flappix.github.io/web_intonation/
Source code: https://github.com/flappix/web_intonation
Usage
In first block you chose from some presets to start with.
In the scale section you see a box for each scale degree with a corresponding number. 1 is the unison, 2 is the second, 3 is the third, etc.
The ratio field allows you to enter the frequency ratio relating to the root as any mathematical expression. In just intonation a major third has the frequency ratio of 5/4 = 1.25. Try to change that value to 1.3 and hear the change of the sound.
In the keyboard section to can map keyboard keys to scale degrees. By default you can play the scale with a, d, f, g, h, j, ...
Enter multiple keys with comma (in the preset section at the top select chord in field keyboard to see how it works.)
Let me know if you are interested in additional features and feel free to report bug/issues.
