Providing Audio and Ambient Sound simultaneously in ANR Headphones

摘要

In an active noise reducing headphone, a signal processor applies filters and control gains of feed-forward and feedback active noise cancellation signal paths. The signal processor is configured to apply first feed-forward filters to the feed-forward signal path and apply first feedback filters to the feedback signal path during a first operating mode providing effective cancellation of ambient sound, apply second feed-forward filters to the feed-forward signal path during a second operating mode providing active hear-through of ambient sounds with ambient naturalness, and provide an input electronic audio signal to an output transducer via an audio playback signal path during both the first and second operating modes.