Intensity: To TextGrid (silences)...

A command that creates a TextGrid in which the silent and sounding intervals of the selected Intensity are marked.

Settings

Silence threshold (dB)
determines the maximum silence intensity value in dB with respect to the maximum intensity. For example, if imax is the maximum intensity in dB then the maximum silence intensity is calculated as imax - silenceThreshold; intervals with an intensity smaller than this value are considered as silent intervals.
Minimum silent interval duration (s)
determines the minimum duration for an interval to be considered as silent. If you don't want the closure for a plosive to count as silent then use a large enough value.
Minimum sounding interval duration (s)
determines the minimum duration for an interval to be not considered as silent. This offers the possibility to filter out small intense bursts of relatively short duration.
Silent interval label
determines the label for a silent interval in the TextGrid.
Sounding interval label
determines the label for a sounding interval in the TextGrid.

Algorithm

First the intensity contour is evaluated and the intervals above and below the silence threshold are marked as sounding and silent. We then remove sounding intervals with a duration smaller than the Minimum sounding interval duration. This step is followed by joining the neighbouring silent intervals that resulted because of this removal. Finally we remove silent intervals with a duration smaller than the Minimum silent interval duration. This is followed by joining the neighbouring sounding intervals that resulted because of this removal.

Experience showed that first removing short intensity bursts instead of short silences gave better results than doing it the other way around.

Important

The effectiveness of the Minimum silent interval duration and Minimum sounding interval duration depends on the effective analysis window duration that was used to determine the intensity contour. For example, if you have chosen 100 Hz for the "Minimum pitch" parameter in the Sound: To Intensity... analysis, the effective analysis window duration was 32 ms. Don't expect to find sounding or silent intervals with a duration smaller than this effective analysis window duration.

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© djmw, December 1, 2006