Kate had a good point. Imagine how much noise a subwoofer can make. Now think of how little it actually moves..

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Actually, a normal speaker - not a subwoofer - would be an even better example because it moves even less compared to its apparent loudness, and balloons also pop at frequencies higher than subwoofer sounds. It makes sense that the popping of a balloon would be like the motion of a speaker when you consider that the air inside the balloon is suddenly all decompressing at once. This is actually not too unlike what happens during an explosion..

edit edit:

"If you yell heartily and continuously for 8 years, 7 months and 6 days, you will have produced sound energy enough to heat a single cup of coffee!" -Google