US Patent 9524098 Methods and systems for subwoofer calibration

Methods and apparatus are disclosed for subwoofer calibration. An example method includes determining a crossover frequency of a playback system, and the playback system includes the subwoofer and a playback device. The example method includes the subwoofer and the playback device configured to output a multimedia content in synchronization. The example method also includes outputting from the subwoofer and the playback device a series of tones near the crossover frequency. The example method also includes prompting a user to select a tone set from the series of tones, and includes automatically adjusting a phase of the subwoofer in relation to the playback device based on the user selection.