The idea of resonances and responses as a fundamental compositional principle is found in many of my compositions. I have used it in instrumental pieces both with and without electronics, in theatre contexts, in conceptual works and in intertextual and intermusical referential structures. In Terpsichord, a piece for percussion and pre-recorded sounds, the resonances from the acoustic instruments form sonic bridges to the pre-recorded electronic sounds, that, in turn, prolong the resonances, re-shaping them into new sonic gestures. A dialogue of actions and reactions is created that drives the trajectory of the music. The term resonance has its origins in acoustics and describes how a vibrating object creates sympathetic vibrations in other objects. It can also be used metaphorically to describe how something we hear or see can be set in motion within us, evoking associations or strong emotions, and how works of art are reinforced and reflected in other works with similar features. In this article I present examples from my own works discussing how resonances and responses are used in solo instrumental pieces with electronics, concerto works, as well as in theatre music works.