In the “Ground” series, which consists so far of six pieces, the principle of the passacaglia is employed throughout, although each time in a slightly different way. For instance, Ground III, for four celli, is based on a fairly constant motif which is joined by a series of contrasting variations, whereas Ground IV is a free piece where the passacaglia motif emerges as the result of a transformation process.
Already present melodically in the intensely expressive first part, it is in the dance that it develops its rhythmical shape within an often stubborn and erratic rhythmic cycle.
Only after the second episode does the ground bass appear, in the form of a duo, opening up to a succession of frenetic tempo variations. In the final episode of this progressive piece the expressive and rhythmic motifs of the first two periods return gradually, carried away by the very logic and seething of the passacaglia.
Thierry Escaich
Translation: Eileen-Rose McFadden