Audio Delay Finder 

Audio delay finder performs a single task - it measures the signal delay between two audio input channels.

For example, comparing the signal delay between music fed to a loudspeaker system and the signal from a microphone, placed some distance away from the loudspeaker. This information is useful for time-alignment of auxiliary loudspeaker systems, so that sound arrival times from the primary and auxiliary systems can be made coincident, as is done in sound reinforcement applications.

In the absence of signal coloration and strong reflections from surfaces, ADFB will display a principal peak corresponding to the sound propagation delay between loudspeaker and microphone. (Nonlinear phase response, reflections from surfaces, etc. will contribute other peaks). For example, with a microphone placed 20 feet from a loudspeaker, the signal driving the loudspeaker fed to Macintosh sound input channel 1 and the signal from the microphone directed to channel 2, ADFB would show a principal peak at 18.18 milliseconds (presuming nominal sound propagation velocity of 1100 feet / second; affected by atmospheric pressure, humidity, etc.)