Improvisation in Classical Music
In Classical music, modern listeners are mostly unaware of the fact that many of the great composers of the past were not only excellent performers but also great improvisers. Starting with J.S. Bach (1685-1750), the greatest composer of the Baroque era, he in fact made his living through his great skill as an improvisor. It was common for the Lutheran Church organist of his day to be able to improvise on choral melodies and Bach was considered one of the greatest at this. There are written accounts of other composers improvisational abilities including Mozart (1756-1791), Beethoven (1770-1829), and Franz Liszt (1811-1886). Yet, as time went on, improvising gave way to the composer's desire to exert complete control over his music. By the late 19th century, improvising was rare and not used at all in public performances of classical music.
In summation, we can say that Jazz and Classical music represent two approaches to Art Music. The Classical composer or performer has a long and rich body of music in written form that he uses to learn from while the Jazz musician uses a body of recorded music to learn. Because of it's small size, the modern Jazz ensemble allows loose interaction while the symphony orchestra's large size and diversity of instruments provides many different sounds and wide dynamic range. In classical music the composer strives for control; he uses printed music to guide and direct the musicians through the conductor. In Jazz music, the songs are loosely composed, thus forming a basis for individual expression within an ensemble. When you go to hear a symphony, you hear an orchestra conducted by the conductor playing a composition. When you go to a Jazz club you hear a small jazz ensemble interacting and improvising a song. Both of these kinds of music provide rich expression and detail to the serious listener. They take different paths to reach their final form but give a person equal opportunities to appreciate the creative output of each.