Canon at the tenth (with counterpoint at the third) from J. S. Bach's Art of Fugue, performed by Kimiko Ishizaka, with an animated graphical score.
Q: Why do the notes sometimes not line up?
A: In this canon, Bach takes liberties with the transposition. So, for example, when the subject is played in D minor, the interval between the second and third notes is a minor third (D to F), but when it's played transposed up a third, that interval is a major third (F to A). Also, even when the notes are played at the same transposition, Bach sometimes adds accidentals to make the harmony work better. And, in the first version of this video, part of the misalignment was just a small calculation error (my fault), which I is fixed in a second version (which has some other small improvements):
Q: I don't understand what's going on ... why does the same circle mean different things at different times?
A: In the first version of this video ...
... (and the first remake) the notes of each section were transposed in pitch and time so that the section began on the same pitch; the notes in the bass required two transpositions, and the notes in the soprano required three. The information about what the actual pitches were was hidden⎯so the score was not really complete, but more a simplification; this was necessary to get the graphical score as compact and clear as it is. In this version (which requires a very wide screen and the highest possible resolution/quality to see adequately) ...
... all the notes are at their proper pitch level, and only transposed in time to show when the same melody is being used. In this video, the different transpositions are color-coded (green=unison/octave, red=3rd, blue=fifth) and there are colored "staff lines" showing the corresponding pitches relative to the key of the piece (D=green, F=red, A=blue);
Q: Please tell me more about this recording.
A: Kimiko Ishizaka recorded the preludes and fugues Bach's Art of Fugue and put the recordings in the public domain as part of the Libre Art of the Fugue, which you can read more about here:
Q: Can you explain more about these Art of Fugue animations?
A: I've written about the process of making them here:
Q: I appreciate the animated graphical scores you make; how can I support your work?
A: Thank you! The easiest way to support my work is by contributing via Patreon:
If you'd like to help in more specific way, consider this:
Q: Could you please do a MAM video of _________?
A: Please read this ...