Bach - Brandenburg Concerto No. 4 In G Major, BWV 1049

 The 4th concerto in the set is written for 2 flutes, solo violin, strings and continuo.  Bach labels the flutes as 'flauti d'echo', and musicologists are not quite sure what specific instrument (or instrument technique) that Bach wanted. Since Bach called the two instruments flauto (flauti in the plural), many consider that it was the recorder that Bach wanted, as otherwise he would have put in the score flauto transverso, or side-blown flutes. Many modern performances use the recorder, but there are some that use the side-blown flute. It is rather a moot point, as the music shines no matter what instrument is used. 

I. Allegro - The recorders play without the solo violin to a sparse downbeat accompaniment as the first movement begins. They play without the solo violin for a considerable amount of time before the soloist enters and the three instruments weave together.  Later in the movement, the violin makes up for its silence in the beginning as it soars in virtuoso double stops, runs, and arpeggios. Based on this, this concerto could almost be considered a violin concerto. Bach's experiment with form and instrument uses makes for a hybrid form of concerto; a cross between a solo concerto and a concerto grosso.  

II. Andante - The slow movement of this concerto is the only one of the set that has all the instruments participate. It is the recorders that contribute the most, as the solo violin is reduced to playing an accompaniment to them. The movement is in E minor, the relative minor of G major. The movement ends with an unresolved chord that leads to the last movement.

III. Presto - The final movement begins with a fugue played by the strings. The solo violin enters and ushers in the recorders as ideas are bounced back and forth by the soloists and strings in contrapuntal style.  

This concerto was also converted to a concerto for harpsichord, recorders and strings, BWV 1057. It is interesting to note that many of Bach's harpsichord concertos were originally for violin. In this reworking, Bach transposes the music down to F major and gives the violin part of the original to the harpsichord. 

The first video is the original Brandenburg Concerto No. 4. The second video is the arrangement Bach made of it, the Harpsichord Concerto No. 6.