AUDIOPLETHYSMOGRAPHY CALIBRATION

Techniques and apparatuses are described that perform audioplethysmography calibration. Provided according to one or more preferred embodiments is a hearable (102), such as an earbud, that is capable of performing a novel physiological monitoring process termed herein audioplethysmography (110), an active acoustic method capable of sensing subtle physiologically-related changes observable at a user's outer and middle ear (108). The hearable (102) can utilize audioplethysmography (110) to monitor a user's biometrics, recognize facial behaviors, and/or sense an environment using acoustic signals. The techniques for audioplethysmography calibration enable the hearable (102) to dynamically select frequencies that improve the performance of audioplethysmography (110). With audioplethysmography calibration, the hearable (102) may utilize different frequencies for different ears (108) and these frequencies may change over time.