1 / 34

Vowels, part 4

Vowels, part 4. March 19, 2014. Just So You Know. Today: Source-Filter Theory For Friday: vowel transcription! Turkish, British English and New Zealand English For next Wednesday: Production Exercise #3 (on Vowels, natch) Formant Measuring Exercise. The Great Lakes Shift.

aine
Télécharger la présentation

Vowels, part 4

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Vowels, part 4 March 19, 2014

  2. Just So You Know • Today: Source-Filter Theory • For Friday: vowel transcription! • Turkish, British English and New Zealand English • For next Wednesday: • Production Exercise #3 (on Vowels, natch) • Formant Measuring Exercise

  3. The Great Lakes Shift • One chain shift is currently taking place in the northern United States. • Prevalent in Chicago, Detroit, Cleveland, Buffalo, and many places in between • (but not in Toronto) • (but maybe in Windsor!) • GeneralGreat Lakes

  4. fronting

  5. [æ] raising

  6. backing “ahead”

  7. Female Talkers

  8. Female Talkers

  9. New Zealand Vowel Shift http://www.youtube.com/watch?v=JT5AQIlmM0I

  10. A Word of Caution • The vowel system of English can vary greatly from one dialect to another. • Ex: the vowels of Canadian English have shifted away from their American counterparts… • (for some, but not all, speakers) • Shift #1:  Unshifted: Unshifted: • Shift #2:  • There are also new shifts underway! • Shift #3:  “head” • Shift #4:  “hid” • Shift #5:  “hood”

  11. Source/Filter Theory: The Source • Developed by Gunnar Fant (1960) • For speech, the source of sound = complex waves created by periodic opening and closing of the vocal folds

  12. Source Differences adult male voice (F0 = 150 Hz) child voice (F0 = 300 Hz)

  13. Just So You Know • Voicing, on its own, would sound like a low-pitched buzz. • Check out the sawtooth wave spectrum: • Vowels don’t sound like this because the source wave gets “filtered” by the vocal tract.

  14. “Filters” • For any particular vocal tract configuration, certain frequencies will resonate, while others will be damped. • analogy: natural variation/environmental selection • This graph represents how much the vocal tract would resonate for sinewaves at every possible frequency.

  15. Source + Filter = Output + =

  16. A Vowel Spectrum F1 F2 F4 F3 Note: F0  160 Hz

  17. Output Example: [i] • Different vowels are characterized by different formant frequencies. • These reflect changes in the shape of the sound filter. • (the vocal tract)

  18. Vowel Spectrum #2: [i] F1 F3 F2 F0 = 185 Hz

  19. at different pitches 100 Hz 120 Hz 150 Hz

  20. Narrow-Band Spectrogram • A “narrow-band spectrogram” clearly shows the harmonics of speech sounds. • …but the formants are less distinct. harmonics

  21. Wide-Band Spectrogram • By changing the parameters of the Fourier analysis, we can get a “wide-band spectrogram” • This shows the formants better than the harmonics. formants

  22. Wide-Band Spectrogram • By changing the parameters of the Fourier analysis, we can get a “wide-band spectrogram” • This shows the formants better than the harmonics. F3 formants F2 F1

  23. Wide-Band Spectrogram • By changing the parameters of the Fourier analysis, we can get a “wide-band spectrogram” • This shows the formants better than the harmonics. F3 formants F2 F1 voice bars (glottal pulses)

  24. Spectrographically • This is what it looks like when you change the source independently of the filter. • The formants stay the same, but the F0 and harmonics change.

  25. The Flip Side • This is what it looks like when you change the filter independently of the source. • The resonating frequencies change, but the F0 and harmonics stay the same.

  26. More Relevantly • In diphthongs, the filter changes while the source can remain at the same F0. “Boyd” • Check out the narrow-band spectrogram…

  27. More Music • With (most) musical instruments, we can only change the frequency of the sound source. • Timbre is a musical term for the “quality” of a sound. • I.e., its characteristic resonances. • E.g., compare the same note played by a trumpet vs. a violin. • In speech, you can independently change both source and filter frequencies at the same time. • Like changing the size of a piano… • As you press different keys on the keyboard. • This makes the acoustics of speech at least twice as complex as the acoustics of music.

  28. Formant-Reading Tip #1 • Another distinction between source and filter characteristics is formant bandwidth. • Harmonics are exact: • integer multiples of source frequency • Resonances are less exact: • they’re centered around an optimal frequency, but other frequencies may resonate to some extent, too. • Hence: formants can appear to merge in wide-band spectrograms.

  29. Bandwidth

  30. Bandwidth

  31. Merged Formants F2 F1

  32. Another Problem: Dynamics F2 F2 F1 F1 “hod” • vowel formants are typically not “steady-state” for very long

More Related