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The Vocal Tract (VT) Source-Filter Theory of Speech Production Capturing Speech Dynamics The Vowels The Diphthongs The Glides The Liquids. Unit 3 outline. Articulation: Lecture Outline. Brief anatomy review Introduction to Source-Filter Theory Introduction to tube acoustics.
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The Vocal Tract (VT) Source-Filter Theory of Speech Production Capturing Speech Dynamics The Vowels The Diphthongs The Glides The Liquids Unit 3 outline SPPA 403 Speech Science
Articulation: Lecture Outline • Brief anatomy review • Introduction to Source-Filter Theory • Introduction to tube acoustics SPPA 403 Speech Science
Supraglottal (Articulatory) system • Comprised of • Cavities • Articulators SPPA 403 Speech Science
Supraglottal Cavities? SPPA 403 Speech Science
Supraglottal Cavities • Oral • Nasal • Pharyngeal • (Buccal)-cavity between the teeth and cheek SPPA 403 Speech Science
nasal cavity oral cavity pharyngeal cavity SPPA 403 Speech Science
The vocal tract SPPA 403 Speech Science
Immobile articulators? SPPA 403 Speech Science
Immobile articulators • Hard palate • Teeth SPPA 403 Speech Science
Hard Palate SPPA 403 Speech Science
Teeth SPPA 403 Speech Science
Mobile articulators? SPPA 403 Speech Science
Mobile articulators • Pharyngeal walls • Soft Palate • Mandible • Tongue • Face, lips and cheeks SPPA 403 Speech Science
Pharyngeal walls SPPA 403 Speech Science
Soft palate SPPA 403 Speech Science
Mandible SPPA 403 Speech Science
Tongue SPPA 403 Speech Science
Face, lips and cheeks SPPA 403 Speech Science
The vocal tract SPPA 403 Speech Science
The Vocal Tract (VT) Source-Filter Theory of Speech Production Capturing Speech Dynamics The Vowels The Diphthongs The Glides The Liquids Unit 3 outline SPPA 403 Speech Science
Simplifying the vocal tract into “tubes” and “valves” SPPA 403 Speech Science
Simplifying the vocal tract into “tubes” and “valves” SPPA 403 Speech Science
The “tube” and “valve” analogy • Tubes… • Act as an acoustic resonatoror filter • Valves… • Open and close the vocal tract to some tubes • velopharyngeal port • Oral articulator approximations • Serve as sound source • Larynx (glottal spectrum) • Within the vocal tract (i.e. /s/) SPPA 403 Speech Science
Source-filter theory of speech production • The sounds we hear as speech is a function of • Sound source • Vocal tract filtering • source and the filter are independent of each other SPPA 403 Speech Science
Source-filter theory simplified SPPA 403 Speech Science
Name that vowel! Same source, different filters SPPA 403 Speech Science
“Larynx? We don’t need no stinking larynx…” SPPA 403 Speech Science
Source characteristics • The source • does not have to be the larynx • does not have to be periodic SPPA 403 Speech Science
Passing white noise through the filter SPPA 403 Speech Science
Passing white noise through the filter SPPA 403 Speech Science
Same source, different filters SPPA 403 Speech Science
Vocal tract as a tube SPPA 403 Speech Science
Vocal tract as a tube • Tubes have physical characteristics • Tubes are acoustic resonators • Acoustic resonators have frequency response curves (FRC) • Physical characteristics dictate FRC SPPA 403 Speech Science
Note • Frequency response curve is also termed the transfer function SPPA 403 Speech Science
FRC peaks – resonant or formant frequency Resonators have an infinite number of formants F1, F2, F3 … denotes formants from low to high frequency Frequency response curve (FRC) F1 F2 F3 F4 SPPA 403 Speech Science
Vocal tract as a tube (Figure 9-1) Straight tube, closed at one end, with a uniform cross-sectional diameter Straight tube, closed at one end, of differing cross-sectional diameter Vocal tract: bent tube, closed at one end, with differing Cross-sectional diameter. SPPA 403 Speech Science
Characteristics affecting filter properties • Length. • Cross-sectional area along its length. • Whether it is closed at either or both ends. SPPA 403 Speech Science
Area function of a tube … Area (cm2) Length along tube (cm) SPPA 403 Speech Science
Area (cm2) Length along tube (cm) Area function of a tube • Area function dictates the frequency response curve for that tube SPPA 403 Speech Science
Uniform tube (unchanging area function) closed at one end • First resonance or formant F1 = c/4l Where c=speed of sound (35,000 cm/sec) l = length of the tube SPPA 403 Speech Science
Uniform tube closed at one end • Higher resonant frequencies or formants are odd multiples of F1 For example, • F1 = (c/4l )*1 • F2 = (c/4l )*3 • F3 = (c/4l )*5 SPPA 403 Speech Science
Tube example SPPA 403 Speech Science
What about the vocal tract? • The vocal tract is fairly uniform in its cross-sectional diameter for neutral or central vowel (schwa) SPPA 403 Speech Science
Male vocal tract Average length 17.5 cm F1 = (35000/4(17.5))*1 = 1*35000/70 = 500 Hz F2 = (35000/4(17.5))*3 = 1500 Hz F3 = (35000/4(17.5))*5 = 2500 Hz SPPA 403 Speech Science
Female vocal tract Average length 14 cm F1 = (34000/4(14))*1 = 1*35000/56 = 607 Hz F2 = (35000/4(14))*3 = 1821 Hz F3 = (35000/4(14))*5 = 3035 Hz SPPA 403 Speech Science
Male-female comparison SPPA 403 Speech Science
Articulation in the context of source-filter theory • neutral vocal tract configuration is an example of an articulatory configuration • Articulation systematically changes • the filter properties of the vocal tract • the type of sound source SPPA 403 Speech Science