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enter image description hereHow can we extract the frequency content of an audio signal given the histogram of beat energy versus beats per minutes?

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    \$\begingroup\$ Can you explain what a histogram of beat energy is and how it relates to a base of beats per minute? \$\endgroup\$ – Andy aka Jun 9 '14 at 11:57
  • \$\begingroup\$ I edited my question .Beat energy is incorrect. The histogram refers to a specific type of music (jazz) and shows how many times the respective value of beats per minutes appears to signal. The duration of the signal is 30 sec. \$\endgroup\$ – und3rd06012 Jun 9 '14 at 12:07
  • \$\begingroup\$ It sounds like you've already extracted the frequency content... \$\endgroup\$ – scld Jun 9 '14 at 12:08
  • \$\begingroup\$ See my edited question.Also can you explain further? \$\endgroup\$ – und3rd06012 Jun 9 '14 at 12:19
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    \$\begingroup\$ BPM is a measure of frequency. You already have the frequency content of the clip that is contained between 60 and 200 BPM (or, if you like, 1 and 3.3 Hz). You won't be able to glean any more frequency information from these graphs alone, as they already are in the frequency domain. \$\endgroup\$ – scld Jun 9 '14 at 12:34
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How can we extract the frequency content of an audio signal given the histogram of beat energy versus beats per minutes?

You can't. The histograms you have shown are meaningless in the context of the fourier analysis of the full musical signal. In fact the histograms you have shown don't actually represent any part of the frequency spectrum of an audio signal.

To extract beat information from an audio signal requires demodulation of that signal via a frequency selective envelope detector - this largely loses any other spectral content that you might be wishing to extract.

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  • \$\begingroup\$ You don't think that you'd see some BPM information in the full spectral content? I would imagine that the drum track might have some strong content in the low frequency range but I've never done a spectral analysis of a full song before.....now that I think about it, it would probably be buried. \$\endgroup\$ – scld Jun 9 '14 at 15:31

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