Thanks to Mr. Ellenstein for his observation. Certainly, one could demonstrate this using our app, and we would love to see results from this or any other experiment that physics educators invent to make use of the app!

Incidentally, we know of a music venue in downtown Nashville that has a bar running down the center of the venue (perpendicular to the stage), and they intentionally use subwoofers with flipped phases, to keep the sound level lower near the bar than on the sides where the audience sits.

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