The music in detail: Below the Edge
Below the Edge is the only piece on Sanctuary (Overtones and Deviations) that I wrote for solo 16-tone piano, without any other instruments or sounds. In writing this piece, I was particularly inspired by Olivier Messiaen and the ethereal sound world he creates through repeated patterns in the top octaves of the piano in pieces such as the Vingt regards sur l'enfant-Jésus.
I composed using the same scale I used in Microcosm (these two pieces are really a pair). This scale moves through all of the 16-tone harmonic pitches in turn: it begins with the note that is most "in tune" with standard, Western 12-tone equal temperament: note #1, A. The notes in the scale get progressively more "out of tune", ending with the note that is furthest away from 12-tone equal temperament: note #7, almost exactly halfway between D and E flat. This is the scale that you can hear at the beginning of the piece. I wanted Below the Edge to mirror Microcosm, so whereas Microcosm moves further and further away from equal temperament, Below the Edge begins with the "stranger" notes and ends with notes closer to the ones we're accustomed to hearing in Western music. In Below the Edge, however, this change from unfamiliar to familiar is a sudden one rather than a gradual one. This is due to the fact that I split the scale in half, and composed the first half of the piece exclusively with the more "out of tune" notes. As the second half of the piece begins (at 0:41 in the video above), the sound palette changes instantly to the "in tune" notes of the scale.
You can stream and buy the album version of Below the Edge here, along with the rest of Sanctuary (Overtones and Deviations).