Patent ID: 6970568

Claim:
A method of measuring a system delay time between when a stimulus signal is applied to an input of an electro-acoustic system having at least one acoustic transducer and when a resulting audio signal produced by the at least one acoustic transducer in response to the stimulus signal is detected at a point of measurement, the method comprising: generating a first signal having a repeatable sequence; coupling the first signal to the electronic input of the electro-acoustic system as the stimulus signal, the acoustic transducer generating a resulting audio signal in response; generating a second signal at an initial delay time subsequent to generating the first signal, the second signal having the repeatable sequence of the first signal; converting the resulting audio signal detected at the point of measurement to a corresponding electronic signal; comparing the corresponding electronic signal and the second signal for a plurality of delay times beginning with the initial delay time; generating and recording for the plurality of delay times a corresponding plurality of signed correlation values having magnitudes indicative of the correlation between the corresponding electronic signal and the second signal at the respective delay time; evaluating the plurality of correlation values for a peak correlation value corresponding to the peak correlation between the corresponding electronic signal and the second signal; and selecting the delay time associated with the peak correlation value as the system delay time.