Composed and performed by Ronan Courty, this piece for solo double bass slows down the layers of time by invoking an imagined secular music, somewhere between imaginary folklore and ancient music. Produced acoustically, the violent and obsessive friction of the bow on the string progressively reveals layers of floating harmonics that prolong the suspension of the moment while evoking a kind of electronically produced ambient sound; the illusion created by the emergence of sustained sounds is particularly effective in reverberant spaces (chapel, church, museum, forest, under a bridge, ...) and makes this piece a contemplative and mineral moment. This relationship between acoustic and electronic is dissected on the album where side B explores the parallel dimensions generated by side A, two facets very present in Ronan Courty's work: "Playing Synesthesia is personally an intense and very spiritually precious moment because it's different from my usual instrumental vocabulary, less aesthetic, more raw and hypnotic."