Abstract: A low cost, reliable and accurate audio frequency phase detection system and method includes an audio signal source generating an audio frequency test signal and a phase detector detecting phase reversals in the audio frequency test signal. The signal source may be an active, real time signal generator or a recorded media player playing back a prerecorded signal. The test signal is provided to a user system while the phase detector determines whether or not a phase reversal has occurred in the test signal between the input and output of the user system and illuminates a green or red LED to indicate whether or not a phase reversal has occurred. The test signal includes a lower frequency signal component and a higher frequency signal component that provides a marker for testing the phase of the lower frequency signal component.