if we got all the cats in the world to meow at exactly the same time how loud would it be
Well the average cat meow is like 65/75dB (above speaking volume but below shouting) and there are about 2bn cats in the world, so, by that math, 130-150bn dB. Which is about 100 million jets taking off at once.
Doesn’t work that way - decibels are a logarithmic scale. That is, 20 dB is ten times as loud as 10 dB; 30 dB is ten times as loud as 20 dB; 40 dB is ten times as loud as 30 dB; and so forth.
An easy rule to remember is that, for every factor of ten by which the number of identical sound sources is increased, add ten dB. So if one cat is 75 dB, then:
- ten cats is 85 dB
- one hundred cats is 95 dB
- one thousand cats is 105 dB
- ten thousand cats is 115 dB
… and so forth, until we reach 165 dB for one billion cats.
Thus, two billion cats meowing in unison would be somewhere between 165 dB and 175 dB, or about as loud as a 12-gauge shotgun blast at point-blank range.
You’re still incorrect - things at the same decibel happening at the same time may cause a slight resonation - making the sound seem weird or warped, but it does not make either of them physically louder.
For instance, people cheering in a stadium, at a sports game. Yes, it’s pretty loud, but it’s only as loud as the loudest person talking (or yelling) - the many voices in the room increase the amount of vibrations in the air, but it does not increase their physical sound.
So, if every cat in the world meowed at the same time, it would be about as loud as the loudest cat meowing - around 75 dB.
As loud as an obnoxiously loud, normal cat.