Dual hearing protection system

An in-ear active hearing protection apparatus configured for use in either an independent mode or a dual hearing protection mode, the apparatus comprising:

• a housing sized and shaped for placement at least partially in an ear canal of a user;
• a microphone disposed at least partially within the housing and configured to receive sound for processing;
• a speaker disposed at least partially within the housing and configured to deliver processed sound into the ear canal;
• a control circuit operably coupled to the microphone and the speaker, the control circuit being configured to:
• operate in an independent mode using a first level-dependent function to process the sound received by the microphone;
• selectively switch to a dual hearing protection mode in response to a signal indicating the presence of a second hearing protection system;
• apply a second level-dependent function different from the first level-dependent function;
• and
• generate an output audio signal at a level that is reduced from the sound received by the microphone in both the independent mode and the dual hearing protection mode;
• wherein the second level-dependent function is configured to mitigate distortion resulting from cascading two level-dependent hearing protection devices.