During Dave Wilson's earlier experiments with creating a movable mechanism to align a module with the time domain, he kept coming back to this idea—there was a direct correlation between the acoustic center of the driver and knowing where and when the sound from each of the drivers arrived at his listening  position. With a microphone placed at his listening position, he began running full-bandwidth pulses through the modules. He could see how the pulses varied in arrival time by observing the different transient blips produced by each module. The transient peaks were displayed horizontally (the axis representing time) in his oscilloscope. As he moved the module, the blip it produced moved in relationship to the other pulses, which were, in turn, generated by each of the other modules. He experimented by moving the modules until all of the pulses aligned on the scope. Sure enough, he could immediately hear a substantial improvement in the sound. 

After further experimentation, Dave realized he had discovered a straightforward method to measure the accuracy of loudspeakers within the parameter of the time domain. More importantly, his technique revealed driver misalignments at the position that mattered most—at the listener’s ears.