A dynamic acoustic transparency control mechanism for audio devices such as headphones or earbuds is described. The acoustic transparency level for the device is adjusted based on ambient sound detected using an external microphone. In some configurations, an automatic gain control (AGC) block is utilized in the signal path to automatically boost ambient sound to a designed level. In some configurations, a sound pressure level (SPL) is determined based on sound received at the external microphone and a lookup table is utilized to determine a gain based on the received SPL. In some configurations, the applied gain is determined based on an audiogram associated with the user, obtained with user permission. The acoustic transparency system as described herein is implemented in a low-latency signal path and is well-integrated with feedback noise cancelling system to alleviate occlusion effects. The described techniques can enable users to maintain an awareness of their surroundings while wearing headphones or earbuds.
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Sun, Guohua; Ooi, Leng; and Lee, Jae, "Dynamic Acoustic Transparency Control System", Technical Disclosure Commons, (December 14, 2020)