FFT from Shairport

[AlessandroFerri]

I do not know if this is the right place to illustare my problem. For some time I'm trying to open (access) to the audio stream coming from Shairport to be able to make FFT (Fast Fourier Transform) and then drive the LEDs, or rather, I send music from my iPhone to Pi, I read the audio and I do the FFT to drive the led. My problem is that I can not access or read the audio, while it is running streaming. Does anyone already tackled this problem and managed to solve it? I need an idea, if not a hand.