I was just reading through some online training they have for police, this is related to busting people for sound ordinance, something im sure a few of you have had happen
"Combining Sound Pressure Levels
Suppose we have two identical sound sources, each alone producing the same dB level. So what is the SPL of the combined
sources? It is not the sum of the two. We cannot simply add decibels directly to get the overall effect. The correct
answer is obtained by using the following rule: Each time the number of identical noise sources is doubled, the SPL
increases by 3dB; each time the number is halved, the SPL is decreased by 3dB. This rule is called 3dB doubling or 3dB
How does the 3dB rule help you? Suppose your noise ordinance has an 80dB noise
limit. You cite a violator for causing an 89dB noise level and the case comes to court.
The judge asks you how loud 89 dB is. Knowing this rule of thumb, you are able to
tell the judge that 89 dB is the same noise level that would be generated by 8 identical
vehicles, each producing the maximum allowable sound level of 80 dB. Case
closed!! Be sure to apply the doubling rule contained in your particular ordinance."
"That’s the problem with your generation, you sit around in your vintage t-shirts, with your participation medals and you never actually do anything"