1. A method comprising: monitoring ambient audio proximate to a sound processing device located in an environment, the ambient audio comprising ambient noise and modified output audio propagated into the environment by the sound processing device; analyzing the ambient audio to derive at least one first characteristic; accessing memory to obtain at least one transformation audio from a plurality of stored transformation audio, each stored transformation audio having at least one associated characteristic, a characteristic associated with the at least one transformation audio matching the at least one first characteristic; generating output transformation audio based on the at least one transformation audio to provide modified output audio for propagation into the environment.