On-key indication technique

摘要

Provided is an ON-key indicator which allows the player to visually and easily confirm the ON-key timing and strength on a keyboard instrument. A controller begins to turn on the light-emitting element farthest from a key of interest of light-emitting elements provided for the key of interest at a timing (t-n) going back an arbitrary time period n from an ON-key timing t of the key of interest, sequentially turns on the subsequent light-emitting elements, and turns on the light-emitting element closest to the key of interest at the ON-key timing t.