In the course of the late Intimate period, composers explored extraordinary chromatic alterations of tonality, for instance extended chords and altered chords, which produced new audio "colours". The late 19th century observed a dramatic expansion in the size from the orchestra, and the commercial revolution served to develop better instruments, https://canvas.ucsd.edu/eportfolios/2000/Home/Tubidy__Legal_Access_to_Music_and_Videos