Patent ID: 8199919

Claim:
A method of operating an audio device configured to be inserted in an ear canal, the method comprising: measuring first sound pressure levels (SPL ECR ) of an electrical drive signal directed to an ear canal receiver (ECR) of the audio device during a time period Δt having a plurality of samples; simultaneously measuring second sound pressure levels (SPL ECM ) for acoustic energy received by an ear canal microphone (ECM) of the audio device during the time period Δt; calculating a sound pressure level (SPL) dose (SPL_Dose Δt ) during the time period Δt using the second sound pressure levels (SPL ECM ) of the ECM; combining the SPL dose (SPL Dose Δt ) with an SPL dose of a previous time period to form a total SPL dose (SPL Dose total ); and modifying the electrical drive signal based on the first sound pressure levels (SPL ECR ) of the electrical drive signal and the total SPL dose, such that a value of the total SPL dose is maintained proximate to a SPL dose threshold over time.