A command that creates a MelFilter object from every selected Sound object by band filtering in the frequency domain with a bank of filters.
The filter functions used are triangular in shape on a linear frequency scale. The filter function depends on three parameters, the lower frequency fl, the central frequency fc and the higher frequency fh. On a mel scale, the distances fc-fl and fh-fc are the same for each filter and are equal to the distance between the fc's of successive filters. The filter function is:
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H(f) = 0 for f ≤ fl and f ≥ fh |
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H(f) = (f - fl) / (fc - fl) for fl ≤ f ≤ fc |
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H(f) = (fh - f) / (fh - fc) for fc ≤ f ≤ fh |
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© djmw, April 4, 2001