IPhone microphone high-pass filter?

Have a look at Wikipedia's article on High-pass filters especially the section on algorithmic implementation of one .

Using an FFT would be a sledgehammer solution in this case. A simple FIR or IIR filter should suffice, but you need to decide on the design parameters for the filter first, i.e. Cut-off frequency (-3 dB point), pass-band ripple, stop-band gain, and whether you care about phase response or not.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.