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A command that creates a FormantPath object from each selected Sound .
The settings for Time step (s), Maximum number of formants, Window length (s) and Pre-emphasis from (Hz) are as you would set them with the Sound: To Formant (burg)... method. The defaults are 0.005 seconds, 5.0 formants, 0.025 seconds, and 50.0 Hz, respectively.
The following algorithm describes what is going on.
ceiling [numberOfStepsUpDown + 1] = middleCeiling
for istep from 1 to 2 * numberOfStepsUpDown + 1
if istep <= numberOfStepsUpDown
ceiling [istep] = middleFormantCeiling * exp (-(numberOfStepsUpDown - istep + 1) * ceilingStepSize)
elsif istep > numberOfStepsUpOrDown + 1
ceiling [istep] = middleFormantCeiling * exp ((istep - numberOfStepsUpDown - 1) * ceilingStepSize)
selectObject: sound
formant [istep] = To Formant (burg): timeStep, maxNumberOfFormants, ceiling [istep], windowLength, preEmphasis
endfor
This description is approximate because in the "To Formant" step we have to guarantee that all the Formant objects get the same time sampling.
© djmw 20230225