The ancient tuning mode/style called "just intonation" is heard on this release from New Albion. With a harp-like timbre, the instrument allows for playing 24 notes per octave in perfectly tuned intervals. It was recorded in the Cathedral of Saint John the Divine in New York.
Harrison's studies with the physics of sound and his training in Indian classical music showed him about perfectly tuned intervals, as they apply both to singing and conventionally tuned pianos. As a result, he spent two years modifying a grand piano to create the Harmonic Piano. Due to the tuning and design, his playing produces aural overtones and combinations thereof. This is not easy, but engaging, intense listening.