Chris@7: 
Chris@7: Low-frequency spectrogram
Chris@7: =========================
Chris@7: 
Chris@7: This is a Vamp plugin that produces a spectrogram from only the
Chris@7: low-frequency content of a signal.
Chris@7: 
Chris@7: You supply a frequency range and a number of bins, and it returns a
Chris@7: magnitude spectrum containing the requested number of bins, spanning
Chris@7: the frequency range you asked for. It does this by first downsampling
Chris@7: the signal to an integer multiple of the maximum requested frequency,
Chris@7: then calculating a Hann-windowed FFT of an appropriate size and
Chris@7: returning a subset of its magnitudes.
Chris@7: 
Chris@7: Chris Cannam, March 2014