Sinfonia No. 9 in F minor
Three voices in anguished conversation.
Bach composed the fifteen Sinfonias - the three-part companions to the two-part Inventions - by 1723, initially as lessons for his eldest son Wilhelm Friedemann. Sinfonia No. 9 in F minor is the most emotionally intense of the set, a chromatic lament in 12/8 where all three voices move in overlapping suspensions that never quite resolve before the next dissonance arrives.
F minor was rarely used in Baroque keyboard music because earlier tuning systems made it sound harsh. Bach embraced that harshness deliberately: the chromatic subject that opens the piece descends like a sigh, and the imitative entries that follow pile tension on tension in a way that anticipates the expressive language of Beethoven by nearly a century.
Hear three independent singers.
The principal challenge is maintaining the independence of all three voices without letting any one dominate. Isolate each voice in turn - soprano, alto, bass - and sing it aloud before playing it, so your ear learns to follow it through the texture. Once each line is familiar, practice hands together at 50% tempo, listening specifically for the moment each voice enters with the chromatic subject.
Before you practice.
01 What is the difference between a sinfonia and an invention in Bach?
Both are short contrapuntal pieces from the same 1723 notebook. The two-part pieces are called inventions; the three-part pieces are sinfonias. The sinfonia adds a middle voice that must remain independent of both the treble and bass.
02 How difficult is Sinfonia No. 9 in F minor?
It sits at intermediate level: manageable technically but demanding musically because three-voice independence asks each hand to subdivide its attention between voices.
Suspensions are the point, not the problem.
Beginners try to smooth over the dissonant suspensions; advanced players lean into them as expressive high points. Use the loop tool on the first four measures to internalize the subject and its answer, then work outward in four-bar blocks. The 12/8 meter should feel like a slow compound pulse, not a hurried 12 separate beats.
