How to detect sound frequency / pitch on an iPhone?

Question

Hi

I'm trying to find a way to detect sound frequency being recorded by iPhone's Microphone. I'd like to detect whether the sound frequency is going up or down.

Answer 1

you can try to use SCListener. It's a small open-source class and very easy to use

EDIT: The formatter does not like the _ in the name. Here is the link. http://github.com/stephencelis/sc_listener

Answer 2

To detect frequency you should check out the fast Fourier transform (FFT) algorithm.