Basic Spectrogram & Clinical Application
Lab 9
Spectrographic Features of
Vowels
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1st formant carries much information about
manner of articulation
– Vowel, consonant
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Vowels, dipthongs & semivowels- spectral
energy is clustered in formants
– 1st 3 or 4 being important for ecognition
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Vowel sounds appear on spectrograms as
bands of energy that run horizontally
Spectrographic Features of
Vowels
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All English vowels can be recognized on
the basis of the fist 2 formants (F1; F2)
Thus each vowel can be represented as
the relative position of the fist two
formants
F1= Variation in TONGUE HEIGHT
F2= Variation in TONGUE
ADVANCEMENT (front -back)
Two Formant Spectrograms: Front, Back & Central Vowels
Phonetic Quality of Vowels
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Front Vowels:
– Larger separation between F1 & F2
– Small F2 & F3 separation
– Frequency of F1= Tongue height
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Back Vowels:
– Small separation between F1 & F2
– Large separation between F2 & F3
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Central vowels:
– Formant frequencies are evenly spaced
– Moderate jaw opening causes mid-range
F1
F1/F2 Plots of Vowels (Vowel Quadrangle)
Vowel Spectrograms (Wide Band)
Laboratory: Vowel Formants
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Frequency values of vowel formants
depend on the length and shape of the
vocal tract
– Vocal tract length & configuration
– Accuracy of production
Laboratory
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Part I: Measuring formant frequencies
– Wide band spectrogram of “She saw ten
tops”
• Identify the 4 vowels& formant bands
• Why do formant bands change across the
syllable
• Measure F1 and F2 for each vowel
– Half of formants thickness
– Measure at stable portion of vowel and midpoint
– Norms compared to measured values
– Measure F1 & F2 of the vowels and draw
in on example
Laboratory
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Part II: Graphic analysis of formants
– Use spectrograms of vowels provided
• Adult male
• Adult female
• Child
– Measure F1 & F2 of each vowel
– Make a spectrogram of all the vowels
Laboratory
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Part II: Continued
– Graph #1- plot the formant frequencies of the:
• Female in RED
• Male in BLUE
• Child in GREEN
– Explain the relationship between what you just
plotted and a standard vowel quad
– Connect all the /i/ and /æ/ points from each
speaker
– Plot F1 & F2 for the articulatory disordered patient