Formula for total noise?

[thatbox]

What the formula for adding noise amounts? I mean, its not 30db + 30db = 60db. So what is it? How do you calculate your noise total without a fancy noise-o-meter?

 

[CaptnKirk]

Here's a start: Decibels
Looks like you gotta do the math and make a calculated guess.

 

[spanner]

10*log((10^x/10) +(10^y/10) +(10^z/10)......) = total db

doubling noise is a 3db increase in sound. i.e 30db+30db = 33db

 

[Davegod]

Further, high pitched, whining/squeaking noise is very likely to be much more irritating than a deep rumbling in the background - yet can be same dba. Then there's background noise, which can do same thing but maybe more importantly, with a lot of background noise your ears will shut out some of the noise of your comp anyway...

imo best way of guestimating noise is to listen to it and see how irritating it is. Then do whatever it is you do with your comp for a couple of days and see how irritating it is. Um, thats it, sorry

edit: given the 30+30=33 as above, it's important to note a comment in the earlier linked article - "If a sound has 10 times the power of a reference (10dB) we hear it as twice as loud. If we merely double the power (3dB), the difference will be just noticeable. "

 

[mastay]

Decibal is log of intensity, and intensity can be added, subtract, multiplied, divided, (although I am not sure what you would do with the last three operations). For simplicity, do this
Take the db of one say, 3 and take 10^3. Then, db of 4, so 10^4. Add them together and you get 11000. Then take log of 11000. You get 4.04.