Patent attributes
Active noise reduction systems and methods for a helmet with a rigid shell that spatially divides a shell interior from a shell ambiance include receiving at least one desired-sound signal representative of at least one desired sound pattern occurring in the shell ambience, and generating, based on the at least one desired-sound signal, anti-sound that is configured to interact with internal sound occurring in the shell interior through superposition. The internal sound includes first internal sound components and second internal sound components, the first internal sound components not corresponding to the at least one desired sound pattern and the second internal sound components corresponding to the at least one desired sound pattern. The anti-sound is further configured to attenuate the first internal sound components, and to amplify, not attenuate, or attenuate to a lesser degree than the first internal sound components the second internal sound components.
