The same interpretation changes when a room reshapes the duration, clarity, and spatial presence of sound, asking the performer to listen and respond anew. Every musician knows the brief uncertainty of touching the first notes in an unfamiliar space. A tone remains in the air longer than expected; a chord returns from the walls with surprising fullness; a rapid passage that was transparent in the practice room suddenly acquires density. The performer, the instrument, and the score have not changed. The sound already has. Space affects the duration, clarity, strength, spatial presence, and colour with which sound reaches both performer and listener. It is not a neutral shell around a performance. Every note enters a different field of reflection, absorption, and reverberation before it returns to the ear or dissolves into silence. In that sense, the room participates in the performance. A musician does not need to become an acoustical engineer in order to under...