I'm trying to conduct FFt on some data stored in an array. Ideally I would like to see the sinusoidal components (harmonics/partials) and phase of each to be ably then to write the first 4 harmonics say into another array for visualisation.

I'm not quite up on my FFT outputs, is the real portion in the frequency domain and the imaginary portion in the Amplitude range?

Or, is there a way to do fft outside of audio and just get the first 4 partials of data stored in an array/buffer?

On a side note, what's the difference between the objects [fft~] and [rfft~]