Nota de Gracia (Grace Note) is a live psychoacoustic overlay of field recordings and found sound objects into two simultaneous signals, one stereophonic and one binaural. Such interaction between two nearly identical compositions generates a masking effect, a phenomenon by which certain sounds alter the perception of others. Attuning these deviations reveals an interstice from which to focus on light couplings, dissonances, and asynchronies that blur the outline of what we lose versus what we perceive.