Perhaps I misunderstood what comb filtering is. What do you call it when you walk across the room, playing a single tone, and you can hear the volume go up and down. Also measurable with a sound meter. If you stay in one place, the tone is constant, but moving just an inch one way or the other causes the volume to change. Walking at a slow steady pace is like a ripple effect.

https://docs.google.com/spreadsheet/ccc?...amp;usp=sharing