The prequel to the ‘A Quiet Place’ saga got me thinking.
spoiler alert!
There is a scene in which many humans march towards a safety point. Each individual human would have been relatively quiet, but because there are a lot of them (potentially hundreds), they end up being, as a whole, loud enough to alert the monsters so they get all killed.
This would suggest that many sources of noise which are near to each other and generate more or less the same amount of noise end up adding up so that the end result in dB is more or less the sum of the individual dB levels.
But then again, it’s fiction.
Back to reality, I work in a room full of different servers which have also very different levels of noise. I have noticed that from my standpoint, the noise of the quietest server seems to disappear whenever the loudest is running, so it kind of does blow my mind how our perception of noise works…
This answer makes no sense. Sound comes in waves with crests and throughs. In a controlled setting you can harmonize which effectively matches crests to crests and throughs to throughs. This happens in music with choirs, orchestra etc. In that case indeed sounds adds up.
However, with many random sources at many random frequencies you just get chaotic patterns where sound sometimes cancels out and sometimes adds up. No way that the overall result of this is that it adds up in dB. My first approximation would be that if one source emits 1dB and another also emits 1dB, these roughly add up to 1dB.
A very easy test of this is whether you now hear a very loud buzzing in your ear because at this very moment many people talk at the same time. I guess you know the answer.