No Stupid Questions

I was discussing real world sounds in open air. Yes, destructive interference is something you have to account for when dealing with sound systems. A speaker playing the same sound in the inverse phase will cause issues, but a group of people, as was the topic, will never be anywhere close that precise.

If the concern is safety, as it is in this example, the concern is the worst case. And the worse possible case is when all the sounds interfere constructively.

It's not really a counterargument when I specifically said my logic of ignoring destructive interference doesn't apply in "situations designed to cause it" like two synchronized sinusoids. Most people are not synchronized sinusoids.

Two people will be about 3 dB higher, four people would be 6, eight people would increase the level by 9 dB, sixteen would be 12 dB higher and so on.

This is only the case if they're making identical sounds in phase with each other. The real life scenario of people walking would not scale in this way as there are too many variables. No two footsteps are the same no matter how hard you try.

I just looked for "human speech frequency spectrum" images so i had to tineye it to find it again but this seems to be the source
https://erikbern.com/2017/02/01/language-pitch.html

I cant vouch for its quality, but it seems pretty in depth from a quick scroll.

That's an excellent question, and like most excellent questions I think the answer is 'it depends' but I would bet for 'yes'.

First, 'noise' is a part of the signal we don't want or we don't care about. In op's example they talk about 'two servers' one quieter and another louder. The sounds of these sources is the part of the signal we care about so the sound of the louder server isn't noise in any case. As long as the sound of the quieter server rises above the noise floor and the recording device have the dynamic range to record the sum of the sounds you should be able to 'measure' it (as in pointing to differences in the readings when you turn it on and off) and maybe cancel the other server to some extent by processing it.

Now to this point is a yes but 'it depends' because while the sound of the louder server isn't noise it can rise the noise floor depending on the acoustics of the server room. Some server rooms have lots of reverb and echo, specially when they're not very full, but in my experience most don't, many put these plastic curtains to contain the AC and they dampen sound reflections pretty effectively. But with bad enough acoustics, a very loud 'loud server', and a quite quiet 'quiet' one the sound floor could rise over the quieter server sound.

Disclaimer: this is from the top of my head, I'm tired and not a hundred percent sure this is correct. Don't take any important decisions based in my autistic rambling.

They add up (in the sense of getting louder) if they're harmonized or party harmonized. They cancel out if they're opposing or partly opposing. They become more continuous but not louder if they're out-of-synch.

Yes, normally noise is cumulative

It's pretty easy to think about this in the context of a stadium of people. One person cherring, 10 people cheering, 1000 people cheering. They produce a louder result.

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

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.

Who said I'm offended? Not everyone who critiques something or someone is "offended" you know.

Not the one you asked but - I thought it read more like an exam question than a crapgpt question.

It is this part that rubbed me the wrong way: "Please provide formulas and an example."

That's like the part where the examiner is giving a hints about how the marks will be awarded.

Either way here's my equation: P(Answer | Question and constraint on answer ) < P(Answer | Question)

I assume that's the OOPs intention though; to block out some of the noise from the responses. I only see one formula so far (excluding my stupid one) so I'm not sure if it worked strictly, but I'd be surprised it it hasn't filtered out some answers.