This is my entry for the Secrets of Organ Playing Contest, week 109. I play Buxtehude's Ciacona in e moll, BuxWV 160.
A Ciacona (or Ciaconne) is a musical form where a short bass line is repeated throughout the piece and offers the opportunity for variation, decoration, figuration and melodic invention, both in the other voices as in the bass-line itself. The Ciaconna is very similar to the Passacaglia which is also a set of variations on a short bass melody.
It is actually very difficult to define the difference between the two forms. A difference could be that in a Ciacona the bass melody stays in the bass voice, whereas in a Passacaglia, the variations include the melody being played in the other voices as well.
I don't know whether this is true for all Ciaconas and Passacaglias in existence. It is (mostly) true however for the Ciacona's I am familiar with.
This beautiful Ciacona is no exceptiom. The melody, or harmonic outline, and the variations thereof are restricted to the lowest sounding voice. It sounds 31 times in vrious variations. Can you spot them all|?
The recording was done with the Hauptwerk software and the sampleset, made by Sonus Paradisi, of the Schittger organ in the St. Martini-kerk, Groningen (http://www.sonusparadisi.cz/en/organs/netherlands/groningen-st-martini.html).