I am trying to calculate the FFT of a signal stored in a WAV file using SciPy. I found a solution here, but it seems like we need to perform this step before the FFT:
b=[(ele/2**8.)*2-1 for ele in a] # this is 8-bit track, b is now normalized on [-1,1)
where the signal samples are stored in array
a. Can someone explain the significance of this step?