Voice detection using ear-based devices

This disclosure describes techniques for detecting voice commands from a user of an ear-based device. The ear-based device may include an in-ear facing microphone to capture sound emitted in an ear of the user, and an exterior facing microphone to capture sound emitted in an exterior environment of the user. The in-ear microphone may generate an inner audio signal representing the sound emitted in the ear, and the exterior microphone may generate an outer audio signal representing sound from the exterior environment. The ear-based device may compute a ratio of a power of the inner audio signal to the outer audio signal and may compare this ratio to a threshold. If the ratio is larger than the threshold, the ear-based device may detect the voice of the user. Further, the ear-based device may set a value of the threshold based on a level of acoustic seal of the ear-based device.