Why does sound past a certain volume become shockwaves?
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Sound is just a pressure wave moving through air. It causes the pressure to fluctuate up and down around the normal level and that’s what you hear, but there’s a limit to how low it can go.
All sound metrics are defined in Pascals so we’ll use those. Normal air pressure is about 100,000 Pascals at sea level. A 120 dB sound makes it go between 99,980 and 100,020. A 160 dB sound makes it go between 98,000 and 102,000. A 180 dB sound makes it go between 80,000 and 120,000.
So what happens when we hit 200 dB? It’d want to swing from -100,000 to +300,000 but air pressure can’t go negative you just hit 0 and have a vacuum. The end result is that above about 191 dB you just end up with a shockwave that has pressure climb wayyyy up then drop all the way to 0. Anything with more energy can only make the peak higher but the valley is bottomed out so it looks very different when measured
If you were somewhere like under water or in denser gas then you could maintain a much higher pressure differential and still have useful sound and not just a drop to 0 pressure.
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