Spectral Analysis

1. Spectral Analysis Feburary 24, 2009

2. Sorting Things Out • TOBI transcription homework rehash. • And some structural reminders. • On Thursday: back in the computer lab. • Craigie Hall D 428 • Analysis of Korean stops. • Today: • Wrap up voice quality discussion • Begin examination of spectral analysis • Remember: • mid-term next Tuesday

3. First Off: Fun Transcription Facts • What’s the name at the start of this clip? • Answers: • Louis 9 • Louie 7 • Lewy 1 • Lily 1 • Loinne 1 • [lu.i] 1

4. First Off: Fun Transcription Facts • What’s the word at the start of the last phrase? • Answers: • That’s 4 • It’s 14 • Is 1

5. TOBI Reminders • Every 4 break needs to be aligned with a phrase accent/boundary tone combo: • L-L% (statement) L-H% (continuation) • H-H% (question) H-L% (plateau) • Normally, statements end in an L-L% pattern • Questions end in: • H-H% (yes/no) • L-L% (WH-question) • Every 3 break needs to be aligned with a phrase accent • L- or H-

6. More TOBI Reminders • Every phrase (intonational or intermediate) needs to have at least one pitch accent in it. • Downstepping can only occur after the first H* in a phrase. • Only H* items can be downstepped. • There is no !L* or !L* + H • Don’t make up pitch accents which don’t exist! • Two popular non-options include: • H* + L H + L* • Don’t make up boundary tone combos that don’t exist! • L-H* H*H% L*!H% L*H-

7. Voice Quality Summary • So far, we’ve talked about: • AT LT MC Flow • Modal moderate varies moderate med. • Tense high varies high high • Creaky high low high low • Breathy low varies low high

8. All Three • Jalapa Mazatec has a three-way contrast between modal, breathy and creaky voiced vowels: • Jalapa Mazatec is spoken in southern Mexico, around Oaxaca and Veracruz.

9. One Random Thing • Breathy voiced segments can “depress” the tone on a following segment. • Examples from Tsonga: • Tsonga is spoken in South Africa and Mozambique. • Voiced stops also “depress” tones more than voiceless stops. • depressor consonants • Nobody really knows why.

10. Open Quotient • From EGG measures, we can calculate the “open quotient” for any particular voicing cycle = • time glottis is open • period of voicing cycle • EGG measures show that there are reliable differences in open quotient values between voice qualities. • Breathy voice has a high open quotient • Creaky/Tense voice has a low open quotient • Modal voice is in between

11. 4. Whispery Voice • When we whisper: • The cartilaginous glottis remains open, but the ligamental glottis is closed. • Air flow through opening with a “hiss” • The laryngeal settings: • Little or no adductive tension • Moderate to high medial compression • Moderate airflow • Longitudinal tension is irrelevant…

12. Nodules • One of the more common voice disorders is the development of nodules on either or both of the vocal folds. • nodule = callous-like bump • What effect might this have on voice quality?

13. Last but not least • What’s going on here? • At some point, my voice changes from modal to falsetto.

14. 5. Falsetto • The laryngeal specifications for falsetto: • High longitudinal tension • High adductive tension • High medial compression • Contraction of thyroarytenoids • Lower airflow than in modal voicing • The results: • Very high F0. • Very thin area of contact between vocal folds. • Air often escapes through the vocal folds.

15. Falsetto EGG • The falsetto voice waveform is considerably more sinusoidal than modal voice.

16. Voice Quality Summary AT LT MC Flow Modal moderate varies moderate med. Tense high varies high high Creaky high low high low Breathy low varies low high Whisper low N/A high med. Falsetto high high high low

17. Last but not least, Korean makes an interesting distinction between “emphatic” (or fortis) obstruents and unaspirated and aspirated (lenis) obstruents.

18. What’s going on here? • A variety of things occur during the articulation of fortis consonants in Korean. • Glottis does not open as wide (during closure) as in lenis stops. • Voicing begins more quickly after stop release • Increased airflow in fortis stops. • Higher F0 after stop release. • Vocal folds are “more tense” than in lenis stops. • = greater medial compression • = “squarer” glottal waveform

19. An Actual EGG Waveform • Modal voicing (by me): • Note: completely closed and completely open phases are both actually quite short. • Also: closure slope is greater than opening slope. • Q: Why might there be differences in slope?

20. A Different Kind of Voicing • The basic voice quality in khoomei is called xorekteer. • Notice any differences in the EGG waveforms? • This voice quality requires greater medial compression of the vocal folds. • ...and also greater airflow

21. Why Should You Care? • Remember that the most basic kind of sound wave is a sinewave. pressure time • Sinewaves can be defined by three basic properties: • Frequency, (peak) amplitude, phase

22. Complex Waves • It is possible to combine more than one sinewave together into a complex wave. • At any given time, each wave will have some amplitude value. • A1(t1) := Amplitude value of sinewave 1 at time 1 • A2(t1) := Amplitude value of sinewave 2 at time 1 • The amplitude value of the complex wave is the sum of these values. • Ac(t1) = A1 (t1) + A2 (t1) • Note: a harmonic is simply a component sinewave of a complex wave.

23. Complex Wave Example • Take waveform 1: • high amplitude • low frequency + • Add waveform 2: • low amplitude • high frequency = • The sum is this complex waveform:

24. Another Perspective • Sinewaves can also be represented by their power spectra. • Frequency on the x-axis • Intensity on the y-axis (related to peak amplitude) • WaveformPower Spectrum

25. Putting the two together Waveform Power Spectrum + + = = harmonics

26. More Combinations + = + = • What happens if we keep adding more and more high frequency components to the sum?

27. A Spectral Comparison Waveform Power Spectrum

28. What’s the Point? • Remember our EGG waveforms for the different kinds of voice qualities: • The glottal waveform for tense voice resembles a square wave. •  lots of high frequency components (harmonics)

29. What’s the point, part 2 • A modal voicing EGG looks like: • It is less square and therefore has less high frequency components. • Although it is far from sinusoidal...

30. What’s the point, part 3 • Breathy and falsetto voice are more sinusoidal... • And therefore the high frequency harmonics have less power, compared to the fundamental frequency.

31. Let’s Check ‘em out • Head over to Praat and check out the power spectra of: • a sinewave • a square wave • a sawtooth wave • tense voice • modal voice • creaky voice

32. Spectral Tilt • Spectral tilt = drop-off in intensity of higher harmonics, compared to the intensity of the fundamental.

33. The Source • The complex wave emitted from the glottis during voicing= • The source of all voiced speech sounds. • In speech (particularly in vowels), humans can shape this spectrum to make distinctive sounds. • Some harmonics may be emphasized... • Others may be diminished (damped) • Different spectral shapes may be formed by particular articulatory configurations. • ...but the process of spectral shaping requires the raw stuff of the source to work with.