Examples described herein involve validating motion of a microphone during calibration of a playback device. An example implementation involves a mobile device detecting, via one or more microphones, audio signals emitted from one or more playback devices as part of a calibration process. After the one or more playback devices emit the audio signals, the mobile device determines whether the detected audio signals indicate that sufficient horizontal translation of the mobile device occurred during the calibration process. When the detected audio signals indicate that insufficient horizontal translation occurred, the mobile device displays a prompt to move the mobile device more while the one or more playback devices emit one or more additional audio signals as part of the calibration process. When the detected audio signals indicate that sufficient horizontal translation occurred, the mobile device calibrates the one or more playback devices with a calibration based on the detected audio signals.