Copies low bins from one input and the high bins of the other.
PV_BinWipe.new(bufferA, bufferB, wipe: 0.0)
FFT buffer A.
FFT buffer B.
Can range between -1 and +1.
wipe == 0, then the output is the same as
wipe > 0, then it begins replacing with bins from
bufferB from the bottom up.
wipe < 0, then it begins replacing with bins from
bufferB from the top down.