The Art of Fugue
Now we move into the second “quartet” of fugues (although this section has only three; for some thoughts about the reason for this see my introductory page on AOF’s structure).
The three fugues in this section are stretto fugues, meaning the subject now will appear not in separate entries, as with the first four fugues, but overlapped with copies of itself. The variant of the main AOF subject used in the stretto fugues is this.
You’ll hear this subject at the start of this fugue in the alto voice, and then you’ll hear an inverted copy of it start in the bass when the alto reaches the third bar, at 0:04. From here and throughout, the subject entries come fast and tightly packed, tumbling over one another like a series of waterfalls. At the very end, the regular and inverted subjects appear in the tightest stretto imaginable: completely overlapped in the alto and bass, with all notes of each subject sounding at the same time. (At the same time, the soprano and tenor trace mirrored accompanying lines.)
There are similarities between the cascading material in this fugue and analogous material in Contrapunctus X, a double fugue in which the essential material of this fugue becomes beautifully encompassed within a more sharply shaped main subject.