A method for performing a calibration of an audio playback device (532,534,536,538), the method comprising performing continuous calibration of the audio playback device by repeatedly performing the steps: receiving, via a wide area network, a first stream of audio comprising source audio content to be played back by the audio playback device (532,534,536,538); receiving a second stream of audio comprising a recording of an audio signal output by the audio playback device (532,534,536,538) based on the audio playback device (532,534,536,538) playing the source audio content; calculating an estimated frequency response of the audio playback device (532,534,536,538) based on the received first stream of audio and the received second stream of audio; adjusting acoustics of the audio playback device (532,534,536,538) based on the estimated frequency response; wherein the continuous calibration of the audio playback device (532,534,536,538) runs as a background process while the audio playback device (532,534,536,538) is playing back audio content; and characterized in that: the second stream of audio is recorded via one or more microphones on or in the audio playback device and the continuous calibration of the audio playback device (532,534,536,538) is suspended when one of: non-linearities are introduced during signal processing of the source audio content; a volume setting of the audio playback device is below a threshold level; and a magnitude of spectral content of one or more frequency ranges of the source audio content is less than a threshold level. receiving, via a wide area network, a first stream of audio comprising source audio content to be played back by the audio playback device (532,534,536,538); receiving a second stream of audio comprising a recording of an audio signal output by the audio playback device (532,534,536,538) based on the audio playback device (532,534,536,538) playing the source audio content; calculating an estimated frequency response of the audio playback device (532,534,536,538) based on the received first stream of audio and the received second stream of audio; adjusting acoustics of the audio playback device (532,534,536,538) based on the estimated frequency response; wherein the continuous calibration of the audio playback device (532,534,536,538) runs as a background process while the audio playback device (532,534,536,538) is playing back audio content; and characterized in that: the second stream of audio is recorded via one or more microphones on or in the audio playback device and the continuous calibration of the audio playback device (532,534,536,538) is suspended when one of: non-linearities are introduced during signal processing of the source audio content; a volume setting of the audio playback device is below a threshold level; and a magnitude of spectral content of one or more frequency ranges of the source audio content is less than a threshold level. non-linearities are introduced during signal processing of the source audio content; a volume setting of the audio playback device is below a threshold level; and a magnitude of spectral content of one or more frequency ranges of the source audio content is less than a threshold level.