Remember me? The number of times this happens in 1 second determines the frequency of the sound wave

Frequency If it happens 125 times per second We perceive it as pitch 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

Harmonics Produced by smaller vibrations of the vocal folds If the fundamental frequency is 100 Hz, you’ll have harmonics at 200 Hz, 300 Hz, 400 Hz, etc. We “can’t” hear them

(fundamental frequency) The harmonic series The second harmonic The first harmonic (fundamental frequency)

The glottal wave

A 17-inch tube likes these frequencies

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

Source-filter model The source provides a vowel’s pitch The filter provides a vowel’s quality Independent of each other

Vowel formants

Diphthong formants

A bit more on acoustics Yuning’s video Better video http://hyperphysics.phy-astr.gsu.edu/hbase/sound/stawav.html#c1