Reading Bach from a score, crossing parts.

This morning I was listening to the J. S. Bach Double Violin Concerto in D Minor BWV 1043, a piece most beloved by me. Like the Sixth Brandenburg Concerto the top string parts cross a great deal as Bach's invertible counterpoint or canon style dictate. You notice this if you are looking at the score, but listening will not show it unless you are hearing it live or on a very good recording with excellent acoustical source localization.

In the Double Concerto it is the invertible counterpoint in the two solo parts that cause one soloist to alternatively play higher notes than the other and they switch top melodic lines throughout. Also, the solo parts are doubled in all the tutti passages, making one think of this music as more like a concerto grosso than a two violin concerto. The Mozart Sinphonia Concertante in E-flat for Violin and Viola is much less a Concerto Grosso because although there are tutti passages, the solo parts are much harder than the tutti strings and are therefore not strictly doubled as in the Bach.

In the Sixth Brandenburg Concerto first movement the parts are much more in the style of canon with the parts alternating as leader and follower. In the other movements the counterpoint is more invertible.Either segment of melody can function in the lower or upper voice with another segment below.

One wonders what forces Bach expected for the Brandenburgs. Today we hear many players on a part, but Bach may have written the parts all for soloists. Certainly hearing them on original instruments is a revelation as the thinner sonority reveals why Bach wrote the inner parts that are not often heard in modern performances, but maybe they were also true chanber works intended for a string sextet as in the Sixth Brandenburg.