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“Connecting the dots” How do articulatory processes “map” onto acoustic processes?

“Connecting the dots”

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“Connecting the dots”. How do articulatory processes “map” onto acoustic processes?. Model assumes No coupling with Nasal cavity trachea & pulmonary system. Stevens and House (1955). Model parameters Distance of major constriction from glottis ( d 0 ) Radius of major constriction ( r 0 ) - PowerPoint PPT Presentation

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Page 1: “Connecting the dots”

“Connecting the dots”How do articulatory processes “map” onto acoustic processes?

Page 2: “Connecting the dots”

Stevens and House (1955)Model assumes No coupling with

Nasal cavity trachea & pulmonary

system

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Stevens and House (1955)Model parameters Distance of major

constriction from glottis (d0)

Radius of major constriction (r0)

Area (A) and length (l) of lip constrictionA/l conductivity index

Figure 1.

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Comparing model to real vocal tract

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Stevens and House (1955)

Figure 2.

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Key Goal of Study Evaluate the effect of systematically changing

each of these three “vocal tract” parameters on F1-F3 frequency

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Form

ant F

requ

ency

(K

Hz)

Point of Constriction (d0) (cm from glottis)

F1

F2

F3

Figure 3.

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Form

ant F

requ

ency

(K

Hz)

Point of Constriction (d0) (cm from glottis)

F1

F2

F3

Figure 3.

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Point of constriction

A/l

NOTE Single intersection

between F1 & F2 in most cases

Figure5.

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Point of constriction

A/l

Figure 5.

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Point of constriction

A/l

Figure 7.

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General Observations

∆ d0 = ∆ Vfront & Vback

↑ d0 = ↓ Vfront = ↑ F2

↑ d0 = ↑ Vback = ↓ F1

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General Observations

↓ r0 = ↓ F1

↑ r0 = ↑ F1

When d0 ↑ (anterior)

↓ r0 = ↓ Vfront = ↑ F2

↑ lip rounding

= ↓ A/l

= ↓ F1 & F2

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Formant Patterns for the “Noncentral” (i.e., omitting

/ú/ and /ü/) Monophthongal Vowels of American English (based on Peterson & Barney averages)

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Formant Data for Men “Standard” F1-F2 Plot

r0

d0

- +

-

+

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Peterson & Barney Averages (for men only) Plotted on an Acoustic Vowel Diagram

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20

“normalizing” formant values

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Clinical Example

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22

Acoustic variables related to the perception of vowel quality F1 and F2 Other formants (i.e. F3) Fundamental frequency (F0) Duration Spectral dynamics

i.e. formant change over time

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How helpful is F1 & F2?

Data Source Human Listeners Pattern Classifier

Peterson & Barney (1952)

94.4 % 74.9 %

Hillenbrand et al. (1995)

95.2 % 68.2 %

From Hillenbrand & Gayvert (1993)

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How does adding more variables improve pattern classifier success? F1, F2 + F3

80-85 %

F1, F2 + F0

80-85 %

F1, F2 + F3 + F0

89-90 %

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How about Duration?

Nearby vowels have different durations

___________________________________

American English Vowels Have Different Typical Durations

___________________________________

/i/ > /I/

/u/ > /U/

/A/ > /‰/

/å/ > /ú/

/Ø/ > /å/ ___________________________________ ___________________________________

Do Listeners Use Duration in Vowel Identification?

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RESULTS

Original Duration: 96.0%

Neutral Duration: 94.1%

Short Duration: 91.4%

Long Duration: 90.9%

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CONCLUSIONS

1. Duration has a measurable but fairly small overall effect on vowel perception.

2. Vowel Shortening (-2 SDs): ~5% drop in

overall intelligibility 3. Vowel Lengthening (+2 SDs): ~5% drop in

overall intelligibility 4. Vowels Most Affected: /å/ - /Ø/ - /ú/

/A/ - /‰/ 5. Vowels Not Affected: /i/ - /I/

/u/ - /U/

What about Duration?

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What about Duration?

Some examples

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What about formant variation?

Notice that some vowels – especially /A/ and /I/ – show a fair amount of change in formant freq’s throughout the course of the vowel. Is it possible that these formant movements are perceptually significant?

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What about formant variation?

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Naturally spoken /hAd/

Synthesized, preserving original formant contours

Synthesized with flattened formants

What about formant variation?

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Conclusion: Spectral

change patterns do matter.

What about formant variation?

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What do we conclude?

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Sinewave Speech Demonstration

Sinewave speech examples (from HINT sentence intelligibility test):

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Selected issues that are not resolved What do listener’s use?

Specific formants vs. spectrum envelope What is the “planning space” used by

speakers? Articulatory Acoustic Auditory