SPL vs. octave band from SPL vs. f
 

Hello FOAMERS.
I don't know if this is the correct place for this thread.
I have some acoustic results formed by libAcoustic (Curle Analogy) in terms of (SPL vs. frequecny) And I want to represent it in terms of (SPL vs octave band or 1/3 octave band) and then calculate the noise criterion NC after the A weighting presses.
My matlab experience is not that much to work this on my one (it's been days and days of trying), so any one can help me with this by sharing some matlab codes or any thing else.
thanks in advance :).

Regards.

A Habib.