US Patent 9749744 Playback device calibration

Systems and methods are provided for device playback calibration. An example implementation involves a computing device receiving, via a microphone, detected audio content rendered by at least one playback device. The implementation also involves the computing device modulating the detected audio content with a modulation signal such that the modulation signal has a modulation frequency determined based on an input frequency range of a processing unit. The implementation also involves providing the modulated audio content to the processing unit; and determining, via the processing unit, an equalization setting for the at least one playback device.