Remember me

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• The number of times this happens in 1 second
  determines the frequency of the sound wave

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Frequency

• If it happens 125 times per second
• 125 cycles per second
• 125 Hertz (Hz)
• We perceive it as pitch
• middle C (about 260 Hz)
• The higher the frequency the higher the pitch
• This is the fundamental frequency
• But there are other frequencies too

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Harmonics

• Produced by smaller vibrations of the vocal folds
• If the fundamental frequency is 100 Hz, youll
  have harmonics at 200 Hz, 300 Hz, 400 Hz, etc.
• We cant hear them

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The harmonic series
The second harmonic
The first harmonic (fundamental frequency)
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The glottal wave
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A 17-inch tube likes these frequencies
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Source-filter model

• The complex wave produced during a vowel is the
  result of two things
• The waves produced by the vibrating vocal folds
  (the source)
• The way certain frequencies of the waves are
  amplified by the oral tract (the filter)
• The vocal folds are a sound source, the oral
  tract is a sound filter
• Example

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Source-filter model

• The source provides a vowels pitch
• The filter provides a vowels quality
• Independent of each other

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Vowel formants
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Diphthong formants
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A bit more on acoustics

• Yunings video
• Better video
• http//hyperphysics.phy-astr.gsu.edu/hbase/sound/s
  tawav.htmlc1