One of the types of objects in Praat, for changing the pitch and duration contours of a sound.
Inside a manipulation object
With Inspect, you will see the following attributes:
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timeStep
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the time step (or frame length) used in the pitch analysis. A common value is 0.010 seconds.
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pitchFloor
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the minimum pitch frequency considered in the pitch analysis. A common value is 75 hertz.
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pitchCeiling
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the maximum pitch frequency considered in the pitch analysis. A common value is 600 hertz.
A Manipulation object also contains the following smaller objects:
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1. The original Sound.
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2. A PointProcess representing glottal pulses.
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3. A PitchTier.
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4. A DurationTier.
Analysis
When a Manipulation object is created from a sound, the following steps are performed:
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1. A pitch analysis is performed on the original sound, with the method of Sound: To Pitch.... This uses the time step, pitch floor, and pitch ceiling parameters.
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2. The information of the resulting pitch contour (frequency and voiced/unvoiced decisions) is used to posit glottal pulses where the original sound contains much energy. The method is the same as in Sound & Pitch: To PointProcess (cc).
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3. The pitch contour is converted to a pitch tier with many points (targets), with the method of Pitch: To PitchTier.
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4. An empty DurationTier is created.
Resynthesis
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A Manipulation object can produce Sound input. This Sound can be computed in several ways:
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• overlap-add: from original sound + pulses + pitch tier + duration tier;
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• LPC: from LPC (from original sound) + pulses + pitch tier;
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• from the pulses only, as a pulse train or hummed;
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• from the pitch tier only, as a pulse train or hummed.
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