IX KLA VIER E is a musical performance in which Nick Acorne alternates between nine pianos. These are arranged spatially in three levels above each other, in an oversized type case, and not perfectly tuned to allow for microtonal harmonies while improvising. To be able to play on the six-meter-high construction, a climbing protection device is installed in the room, enabling the musician to move freely within the piano matrix.

In IX KLA VIER E, Acorne wants to take the idea of musical performance to the point of absurdity. He places the examination of time, sound, space, silence, and their combination at the center of his composition. Simultaneously with musikprotokoll, the Cornhub.today vinyl record is being released, on which Acorne plays the nine pianos simultaneously, thanks to multitrack technology.