# why are crowds louder than small groups/individuals even if each person produces the same amount of noise? In other words why would a group of people, each generating noise at Xdb sound louder than an individual generating noise at Xdb? How does cumulative sound work?

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why are crowds louder than small groups/individuals even if each person produces the same amount of noise? In other words why would a group of people, each generating noise at Xdb sound louder than an individual generating noise at Xdb? How does cumulative sound work?

In: Physics

Air pressure. Same reason a guitar amp with a 1×12 cab is significantly “quieter” than the same amp on a 4×12 cab.

More people means more sound waves being generated. More sound waves means u hear it louder and more further away.

Sound intensity (loudness or volume using ELI5) is measured in decibels (dB), like a meter is measure of distance.

So let’s say a crowd of *one* person yelling is 60 dB. What happens if you bring in a second person yelling at 60dB?

Well, 60dB + 60dB does NOT equal 120dB. Because physics, 60dB + 60dB=63dB. When you double the intensity you gain 3dB,which isn’t very much.

So, using the doubling game, you’d need FOUR people to get to 66dB.

Honestly, I’m sitting on toilet right now, so I won’t continue to extrapolate from there. Let’s jump ahead.

Let’s say that you have a good sized crowd, 4000 people, and together they can make a pretty loud crowd roar, 85dB. If you had 8000 people, the noise would be 88dB. A 3dB step is barely noticeably loud. So it would take a lot more people to make a noise level of 100dB, which is pretty darn loud.

Of course this does not take into account the acoustics of the stadium, and not everyone make the same amount of noise, etc.

Hope this helps.

Same reason 2 horses can pull more than one. The power is cumulative.

Sound is just waves of pressure. High pressure followed by low pressure.

It’s more complex than this, since it’s logarithmic among other reasons, but to make it simple, let’s say that a person makes a sound that is at a pressure of “4” above ambient pressure in the peaks of the waves, and “4” below in the troughs. Add another person making the same sound at the same volume at the exact same time, and you get waves of “8” above and “8” below. Those waves move your eardrums twice as much as the single person’s “4” wave.

Interestingly, because it’s waves with peaks and troughs, it’s actually possible to cancel out a sound by generating the exact same wave, but basically upside down, so that any trough lines up perfectly with any peak, and as we know 4 plus negative 4 equals zero.

When people speak, they make sound waves. When multiple people speak, the sound waves collide and combine into new waves with a higher intensity.