An example implementation may involve a computing device detecting a trigger condition that initiates concurrent calibration of multiple playback devices. The implementation may further involve the computing device sending, to at least one of the multiple playback devices, one or more commands that instruct each playback device of the multiple playback devices to repeatedly output a calibration sound according to a sequence. The sequence involves the calibration sound cycling through frequencies of a calibration frequency range and the one or more commands instruct the multiple playback devices to stagger emission of the calibration sounds such that each successive calibration sound is outputted at a delay relative to output of a preceding calibration sound. During the output of the calibration sounds, the implementation may also involve the computing device detecting, via at least one microphone, an audio signal comprising the outputted calibration sounds.