In week 1 we spent a lot of time on wave interference, most notably the comb filter. In week 2, we talked about waves arriving out of time with each other, but not creating a comb filter. When do we get a comb filter; when do we get precedence; when do we get 2 distinct arrivals? It depends a lot on what type of sound you're hearing, but comb filtering usually sets in at 0.05 ms delay, and extends to at least 2 ms delay. From there up to as much as 30 ms and sometimes longer, the delay can be interpreted as precedence. Longer delays than that are perceived as discrete arrivals. If the delay is 3 minutes, for a 2 minute song, you will actually hear the same song twice...

In the first clip, you hear clicks that start in unison. After about 10 seconds, the clicks are delayed by 60 ms. The delay is progressively shortened until the clicks are no longer distinguishable from one another in time, and the character of the click isn't significantly different from the clicks in unison. This defines the precedence range. As the delay gets smaller, you will hear a single click with a different "color" due to comb filtering. At the end of the clip, the clicks sound in unison again.

In the second clip, you may only think there is a single click coming from one of your speakers. There are actually 2 clicks at equal volume, delayed by 2 ms and panned hard left and right. The click to arrive first at your head will probably sound like the only click there is to you due to the precedence effect.

This tendency of your brain to attribute spatial information to the first-arriving information may be conveyed in the Franssen Effect demonstration clip, which may or may not work for you.

The final clip illustrates the inability of your brain to phase lock frequencies above 5 kHz, which makes it impossible to discern a melody. Although there is a great deal of sonic information above 5k, it contributes to timbre rather than pitch.