Redesigning a Piano Roll: A Melody Input Interface That Can Play Microtones with an Arbitrary Number of Keys

A piano roll plays a fundamental role in computer music production. As its name suggests, a piano roll is designed with the motif of a piano keyboard. In DAW software, synthesizers can produce a variety of synthesized sounds and simulated instrument sounds. Although various synthesized sounds and simulated instrumental sounds can be produced using synthesizers, the most common input format is a piano roll with keyboard input.
Although keyboard input is simple, especially for those familiar with it, it has a significant limitation in that notes that can be played are limited to those in 12 equal temperament. It is possible to change the actual frequency of keyboard sound by changing the tuning settings (which is called calibration). However, an input interface based on the concept of a piano keyboard has many limitations in terms of inputting microtones in cases where an octave is not composed of 12 tones (e.g., 17 and 24 equal temperament). Based on these problems, we propose an interface that allows users to customize temperament that can be played by a piano roll and to redesign a piano roll. Specifically, our interface allows users to move back and forth between editing temperaments and creating melodies. The temperament can be created in three different ways. Creating from scratch, editing an existing template temperament, or creating from an imported external audio file.