15.1.10  Visualizing power spectra: plotspectrum

The plotspectrum command displays the power spectrum of an audio clip.

• plotspectrum takes one mandatory and one optional argument:
  • A, an audio clip.
  • Optionally, range, which can be in the form range=[lf,uf] or range=lf..uf, where lf is the lower bound and uf the upper bound of the desired frequency band (by default, range=[0,s/2] where s is the sampling rate).
• plotspectrum(A ⟨range⟩) displays the power spectrum of the audio data on the specified frequency range.
  If the audio clip has more than one channel, the channels are mixed down to a single channel before computing the spectrum.

Example.
Assuming that a male voice is recorded in the file example1.wav:
Input:

Output:

You can see that the dominant frequency is around 220 Hz, which is the middle of tenor range. This is consistent with the fact that a man is speaking in the clip.