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Bandpass frequency filtering


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Many vocal sounds are strongly band-limited, namely the frequency range is narrow relative to the sonogram range (which you can only coarsely control in SAP2011). Take for example this vocalization by a dolphin in a social environment:

dolphin

As shown in the top panel, the mean frequency estimate of a whistle (blue curve, see red arrows) is contaminated by a low frequency sound, which we are not interested in. Using the two band-sliders on the right, we limit the range of feature calculation to that of our whistle of interest, click recalculate and this mean is sufficient to obtain a more reasonable estimate of mean frequency.