Patent ID: 8798283
Filing Date: 2014-08-05
Classification: G10K,H04R

Abstract:
1. An active noise reducing headphone comprising: an ear piece configured to couple to a wearer's ear to define an acoustic volume comprising the volume of air within the wearer's ear canal and a volume within the ear piece; a feed-forward microphone acoustically coupled to an external environment and electrically coupled to a feed-forward active noise cancellation signal path; a feedback microphone acoustically coupled to the acoustic volume and electrically coupled to a feedback active noise cancellation signal path; an output transducer acoustically coupled to the acoustic volume via the volume within the ear piece and electrically coupled to both the feed-forward and feedback active noise cancellation signal paths; and a signal processor configured to apply filters and control gains of both the feed-forward and feedback active noise cancellation signal paths; wherein the signal processor is configured to: replace the first feed-forward filters with second feed-forward filters in the feed-forward signal path during a second operating mode providing active hear-through of ambient sounds with ambient naturalness; and wherein the second feed-forward filters have value K  to be approximately equal to a predetermined target response,