Respiratory-based biofeedback devices, systems, and methods are provided. A respiratory biofeedback method includes producing a respiratory signal in response to a user's respiratory activity, generating an audio output signal that includes a modified version of the respiratory signal, and converting the audio output signal into sound waves output to the user to provide biofeedback. The sound waves can be output to the user in real time response to the user's respiratory activity. A microphone can be used to generate the respiratory signal. The generated audio output signal can includes the respiratory signal modified to increase a volume level of a portion of the respiratory signal where the volume level exceeds a specified volume level.