Do you have a question about the Harman JBL SUB 550P and is the answer not in the manual?
Instructions for powering the subwoofer on, off, and standby modes.
Adjusting the crossover frequency for bass transition.
Setting the subwoofer's volume level for optimal sound.
Adjusting phase for optimal bass impact and clarity.
Procedure for general unit function testing and initial setup.
Testing the subwoofer's frequency response with a sweep signal.
Testing the subwoofer driver's electrical and mechanical operation.