Topic: The Twins (Two Part Invention)
"The Twins (Two Part Invention)" by Hugues Bedouelle is built around a call by one of the two voices and an answer by the other one, and thus around a dialog between them. However, each voice is also interesting in itself. The call is uttered by the top voice in the first half of the piece and by the bottom voice in the second half. The piece is entirely written in the octatonic scale [C, Db, Eb, E, F, G, Ab, Bb], which is invariant by inversion around E. It was divided into two non-equivalent all-interval tetrachords, either [C, Db, Eb, G] and [E, F, Ab, Bb], or [Ab, G, F, Db] and [E, Eb, C, Bb] after inversion, hence the title. The call and response are kept within one of the four tetrachords, which differ according to the section. When one voice speaks in a tetrachord, the other voice speaks in the complementary tetrachord. The form of the piece, in eight sections, derives from the above symmetries. The piece was recorded with Grand C. Bechtein DG Recording 2 and Pianoteq 7.
https://soundcloud.com/hugues-bedouelle/46hb15