Naxxfish

I’ve just finished a big uni project, and I feel like doing something frivolous.  Twig has provided me with something to do:

* Twigathy wonders how many kittens is as noisy as a aircraft taking off >_>

Thank you!

We need some guestimates to start off with.  I’m going to say that an aircraft taking off is about 120dB (from this page), and a kitten’s mew is about 64dB (quite a noisy kitten). Both these figures are dBSPL.

We will say that we have n kittens, and that their mews are incoherant (i.e. at different phases and frequencies – unless they’re exceedingly well trained kittens).  We’re going to assume that they all meow at the same 64dB.  The equation to sum sound pressure levels is:

L_pt = L_ps + 20 log(n)

Where

L_pt = total sound pressure level (dB)

L_ps = sound pressure level from each single source (dB)

n = number of sources

(stolen from Engineering-toolbox.com)

We want to extract the n from the log and make it the subject.

Some algebra later, we get

n = 10 ^ ((L_pt-L_ps) / 20)

If we plug in 120dB for L_pt and 64dB for L_ps.

n = 10 ^ ((120-64) / 20)

n = 630.957

So, there you have it.  It takes 631 kittens all meowing simultaneously to be equivilant to an aircraft taking off.

EDIT: I’ve realised I’ve left a lot of things out, so expect another update with more detail :p