'Where two rivers meet, the water is never calm' is composed for a new digital instrument that I have built. I have document the process thoroughly on my blog. I have called this a 'diplacusis piano' because it is built from piano sounds and reproduces very accurately my diplacusis. Diplacusis is a disturbing phenomenon in which I hear two different notes when a single one is played. These notes are detuned from one another, creating a discordant, bell-like sound. So listening to conventional music becomes a painful and unsettling experience for me.

My challenge was to convert this into something beautiful. I built the instrument by stopping up my ears alternately and singing the pitches I heard, to create a map of the diplacusis. Bear in mind that my hearing loss also means that I have very little perception of low frequencies, which means that low notes are really overtone structures that are themselves detuned by the diplacusis. And then I have hearing loss too, which is much worse in the right ear than the left.

Composing this piece was very difficult. Because I cannot hear the sounds, I have used a visual method which you will see. The scrolling spectrogram shows how the overtone structures of each sound enables me to make connections between notes. I found that the music must be very minimal and quiet, otherwise it rapidly becomes incoherent. The pleasure is in voyaging into each sound as it is made. Every note on the diplacusis piano is really an 8 second composition in its own right. This can also be experienced via the vibrating floor, because I have added a sub-bass track that cannot be heard but only felt.

Here is the score