Abstract: Methods, microphones, and systems are provided for processing sound waves. The sound waves are detected with a portable device (such as a microphone) and an audio signal representing the sound waves is generated. A security layer is applied to the audio signal within the portable device (e.g., by encrypting the audio signal), so that only authorized entities may access the audio signal. The audio signal is then outputted from the portable device to an external computer, which can remove the security layer to access the audio content within the audio signal.

Abstract: Methods, microphones, and processors are provided for processing ambient sound waves. Ultrasound waves are combined with the sound waves to create heterodyned sound waves. The heterodyned sound waves are detected and, in response, a sound detection signal containing information relating to the heterodyned sound waves is generated. A heterodyned audio signal representing the heterodyned sound waves is generated at least partially based on the sound detection signal, and then an ambient sound signal representing the ambient sounds is derived from the heterodyned audio signal.