Chaconne
Variation form over a recurring bass model.
What it means
The chaconne is a variation form over a short, constantly recurring model. What is repeated is either a bass formula or a chord progression of usually four or eight bars, over which ever new variations unfold. The metre is as a rule triple, the tempo measured. The chaconne can hardly be distinguished sharply from the passacaglia: the terms were used inconsistently in history, and the common distinction — bass model there, chord progression here — does not consistently stand up to examination of the sources.
Musical use
Both forms come from the sphere of dance and are developed into large instrumental forms in the seventeenth century. Their appeal lies in the tension between what stays the same and what changes: the ground repeats unchanged while figuration, number of voices, register, and character change above it. From this arise arcs that are built up over many variations — thickening, withdrawal, renewed climax. Later composers, too, take up the principle, into the music of the twentieth century, because it combines strict order with great freedom.
Performance practice
First get an overview of all the variations and plan the course as a whole: where are the climaxes, where the points of rest, where the peak. Without this planning the piece falls apart into individual parts. Keep the basic tempo stable, for the recurring ground is the yardstick; tempo changes have a strong effect here and should be used sparingly. Connect the variations without a break, if the music suggests it. Make the model audible without emphasizing it.
Remember that the model must stay audible without being emphasized: whoever brings it out in every variation makes the form heavy, whoever hides it completely takes away its hold. Watch for the places where the bass progression itself is altered, for they mark larger sections. With keyboard instruments and solo strings, the distribution of the voices across the compass is important so that the variations gain in colour. Plan pauses between groups of variations only where the music suggests them.