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…
Yes, sounds are waves that go thru a medium, usually air.
Think of it like one person speaking in a gym compared to 1,000
The different sounds add up, that’s easy everyone just has to talk. But you don’t get silence, you get a cacophony.
To produce opposite sounds to cancel each other out though, that would be impossible, and becomes even more impossible as you scale up.
It helps if you can see it to visualize what I mean by alternating waves:
https://www.askamathematician.com/wp-content/uploads/2013/01/Noise-Cancellation.gif
I didn’t think of it till I looked for a diagram, but yeah, it’s exactly how active noise cancellation works.
Quick edit:
But headphones are the easiest way to do it because it just controls for sound right outside each ear.
To do that “out in the open” to trick the monsters you’d need something mounted right on what’s making the noise. Like crazy noise cancelling shoes which would still have a slight delay before and after the noise. And ones good enough to work out in nature on u predictable terrain?
Like, cool thought experiment, but no practical way to implement