orcheil is a web application for the visualization of orchestration. The goal is to provide a clear and immediate representation of when an instrument is or is not performing in a piece of music. This can reveal, for instance, the instrumentation of a composite timbre, or the role of orchestration in articulating form. It is a timbre-first visualization of music.
orcheil is driven by symbolic data representing music notation, specifically a MusicXML file. Just upload your file and orcheil will create a visualization of it. You may select a color palette beforehand, and choose to represent dynamic and/or register if you wish.
orcheil is online at http://orcheil.ca/.