Code example drawing WAVE's spectrum analysis image

Is there an example of drawing WAVE spectrum analysis image开发者_高级运维 like the one below?

Preferred language is Python; Ruby also.

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You have to compute the magnitude (magnitude = hypothenus) of each bins(real,imag) of a FFT analysis, then you scale each point, X is a frequency to Pitch function ( frequency = bins index * (SamplingRate / FFTSize)) and Y is an amplitude to decibel function ( applied to each previously computed magnitude.