Nota de Gracia (Grace Note) is the first of a series of psychoacoustic explorations through the opening and spatialisation of a personal sound archive. The piece overlays two simultaneous signals, one stereophonic and the other binaural by layering of field recordings and found sound objects. Such interaction between two nearly identical compositions generates a masking effect, a phenomenon by which certain sounds alter the perception of others. Paying attention to the differences between both reveals an interstice from which to focus on slight couplings, dissonances, and asynchronies that blur the outline of what we lose versus what we perceive.