Vocal Tract Flashcards
What does the vocal tract represent
source and the filter
Describe the source
Natural frequencies of source (vocal fold) vibrations provide driving frequencies of the filter
Describe the filter
Modeled as a tube closed at one end, open at another given that it matches the conditions for the pressure of the waveform (needing a node at open end and antinode for a closed end)
What are formants
Natural resonant frequencies of the vocal tract are called formants
What is the source produce
Produce glottal source signal seen in the saw tooth shape
Fundamental frequency of all even and odd harmonics ( These are natural frequencies of vibration)
What does the filter produce
VT is modeled as a open closed tube which is good model for the schwa. Like a open closed tube, the resonant frequencies consist of a fundamental and odd only harmonics
What is the term for the spectral envelope that depicts the spectral shape of the natural resonant frequencies of the vocal tract?
The curve of the spectral envelope describing what frequencies of the VT are natural frequencies and which get damped is called “vocal tract filter function or “filter curve
What are the other characteristics of the filter
Source produces F0 harmonics and other partials
Filter is forced to vibrate at source driving frequencies, those source frequencies close to filter resonant frequencies are amplifies, others damped
What are the Steven and House rules address
Steven and House findings address the issues of tongue placements and lip rounding and are summarized below
Effects of articulators or formants ( Steven and House Rules)
Describe Steven and House rule on tongue height
Tongue height refers to the relative height of the tongue at the location of the major vocal tract constriction
F1 varies inversely with tongue height, the higher the tongue position the lower the F1 and the effect is much greater for front vowels than back vowels
Describe Steven and House rule on Tongue Advancement
Tongue Advancement: refers to the relative frontness or backness of the major constriction.
F2 varies directly with tongue advancement, the more forward the tongue the higher the F2
F1 varies inversely with tongue advancement, the more forward the tongue the the lower the F1 and the effect is weaker than the effect on F2
These effects are both greater for high vowels than low vowels
Describe Steven and House rule on lip rounding
Lip rounding: Increased lip rounding decreases all formant frequencies
But this affects F2 more than F1 or F3
Effect on F2 is compounded by tongue height, the higher the tongue the more f2 lowers with lip rounding
F1 and F2 are strongly affected by articulatory configurations, F3 less so
Same pattern of formants can sometimes be achieved by different articulatory placements, there is ambiguity in articulatory configuration
What does the vowel space plot
the F1/F2 plot
Describe the universality of vowel identity
If actual values of formant frequencies differ- from speaker to speaker due to differences in vocal tract size, shape, articulation, coarticulation
What are people listening to in order to determine vowel identity- relative ratios of formant frequencies
What are the effects that F1 and F2 has on diphthongs
Not just a combination of vowel, each diphthong had a particular and constant slope of F2 transition despite rate changes. Durations are not well measured but longer than monophthongs
