Behrman Chapter 5, 6

1. Behrman Chapter 5, 6 Place less emphasis on… • Minor anatomical landmarks and features • Extrinsic muscles of the larynx • Blood supply to the larynx • Central motor control of larynx • Peripheral Sensory control of larynx • Stress-Strain Properties of Vocal Folds

2. Laryngeal Activity in Speech/Song • Sound source to excite the vocal tract • Voice • Whisper • Prosody • Fundamental frequency (F0) variation • Amplitude variation • Realization of phonetic goals • Voicing • Devoicing • Glottal frication (//, //) • Glottal stop (//) • Aspiration • Para-linguistic and extra-linguistic roles • Transmit affect • Speaker identity

3. Newborns No layered structure of LP LP loose and pliable Children Vocal ligament appears 1-4 yrs 3-layered LP is not clear until 15 yrs Old age Superficial layer becomes edematous & thicker Thinning of intermediate layer and thickening of deep layer Changes in LP more pronounced in men Muscle atrophy The vocal fold through life…

4. The Glottal Cycle

5. http://video.google.com/videosearch?source=ig&hl=en&rlz=&q=high%20speed%20video%20voice&um=1&ie=UTF-8&sa=N&tab=wv#http://video.google.com/videosearch?source=ig&hl=en&rlz=&q=high%20speed%20video%20voice&um=1&ie=UTF-8&sa=N&tab=wv# Complexity of vocal fold vibration Vertical phase difference Longitudinal phase difference

6. Myoelastic Aerodynamic Theory of Phonation Necessary and Sufficient Conditions • Vocal Folds are adducted (Adduction) • Vocal Folds are tensed (Longitudinal Tension) • Presence of Aerodynamic pressures

7. 2-mass model Upper part of vocal fold Mechanical coupling stiffness Lower part of vocal fold Coupling between mucosa & muscle TA muscle

8. VF adducted & tensed→myoelastic pressure (Pme) • Glottis is closed • subglottal air pressure (Psg) ↑ • Psg ~ 8-10 cm H20, Psg>Pme • L and R M1 separate • Transglottal airflow (Utg) = 0 • As M1 separates, M2 follows due to • mechanical coupling stiffness • Psg > Pme • glottis begins to open • Psg > Patm therefore Utg > 0

9. Utg↑ ↑ since glottal aperature << tracheal circumference Utg ↑ Ptg ↓ due to Bernoulli effect Pressure drop across the glottis Bernoulli’s Law P + ½ U2 = K where P = air pressure  = air density U = air velocity

10. Utg ↑ Ptg ↓ due to Bernoulli effect Plus “other” aerodynamic effects Ptg < Pme M1 returns to midline M2 follows M1 due to mechanical coupling stiffness Utg = 0 Pattern repeats 100-200 times a second

12. Limitations of this simple model

13. The Glottal Cycle

14. Sound pressure wave Instantaneous sound pressure Time

15. Phonation is actually quasi-periodic • Complex Periodic • vocal fold oscillation • Aperiodic • Broad frequency noise embedded in signal • Non-periodic vocal fold oscillation • Asymmetry of vocal fold oscillation • Air turbulence • Voicing vs. whispering

16. Glottal Aerodynamics • Volume Velocity • Driving Pressure • Phonation Threshold Pressure • Initiate phonation • Sustain phonation • Laryngeal Airway Resistance

17. Measuring Glottal Behavior • Videolaryngoscopy • Stroboscopy • High speed video

18. Photoglottography (PGG) illumination Time

19. Electroglottography (EGG) • Human tissue =  conductor • Air:  conductor • Electrodes placed on each side of thyroid lamina • high frequency, low current signal is passed between them • VF contact  = impedance • VF contact  =  impedance

20. Electroglottogram

21. Instantaneous airflow is measured as it leaves the mouth Looks similar to a pressure waveform Can be inverse filtered to remove effects of vocal tract Resultant is an estimate of the airflow at the glottis Glottal Airflow (volume velocity)

22. Flow Glottogram

23. Synchronous plots Sound pressure waveform (at mouth) Flow glottogram (inverse filtered mask signal) Photoglottogram Electroglottogram

24. F0 Control • Anatomical factors Males ↑ VF mass and length = ↓ Fo Females ↓ VF mass and length = ↑ Fo • Subglottal pressure adjustment – show example ↑ Psg = ↑ Fo • Laryngeal and vocal fold adjustments ↑ CT activity = ↑ Fo TA activity = ↑ Fo or ↓ Fo • Extralaryngeal adjustments ↑ height of larynx = ↑ Fo

25. Average F0 speaking fundamental frequency (SFF) Correlate of pitch Infants ~350-500 Hz Boys & girls (3-10) ~ 270-300 Hz Young adult females ~ 220 Hz Young adult males ~ 120 Hz Older females: F0 ↓ Older males: F0 ↑ F0 variability F0 varies due to Syllabic & emphatic stress Syntactic and semantic factors Phonetics factors (in some languages) Provides a melody (prosody) Measures F0 Standard deviation ~2-4 semitones for normal speakers F0 Range Fundamental Frequency (F0)

26. Maximum Phonational Frequency Range • highest possible F0 - lowest possible F0 • Not a speech measure • measured in Hz, semitones or octaves • Males ~ 80-700 Hz1 • Females ~135-1000 Hz1 • 3 octaves often considered normal 1Baken (1987)

27. Fundamental Frequency (F0) Control • Ways to measure F0 • Time domain vs. frequency domain • Manual vs. automated measurement • Specific Approaches • Peak picking • Zero crossing • Autocorrelation • The cepstrum & cepstral analysis

28. Autocorrelation Data Correlation + 1.0 + 0.1 - 0.82 + 0.92

29. Cepstrum

31. Amplitude Control • Subglottal pressure adjustment ↑ Psg = ↑ sound pressure • Laryngeal and vocal fold adjustments ↑ medial compression = ↑ sound pressure • Supralaryngeal adjustments

32. Measuring Amplitude • Pressure • Intensity • Decibel Scale

33. Average SPL Correlate of loudness conversation: ~ 65-80 dBSPL SPL Variability  SPL to mark stress Contributes to prosody Measure Standard deviation for neutral reading material: ~ 10 dBSPL Sound Pressure Level (SPL)

34. Dynamic Range • Amplitude analogue to maximum phonational frequency range • ~50 – 115 dB SPL

35. no clear acoustic correlates like pitch and loudness However, terms have invaded our vocabulary that suggest distinct categories of voice quality Common Terms Breathy Tense/strained Rough Hoarse Vocal Quality

36. Are there features in the acoustic signal that correlate with these quality descriptors?

37. Breathiness Perceptual Description • Audible air escape in the voice Physiologic Factors • Diminished or absent closed phase • Increased airflow Potential Acoustic Consequences • Change in harmonic (periodic) energy • Sharper harmonic roll off • Change in aperiodic energy • Increased level of aperiodic energy (i.e. noise), particularly in the high frequencies

38. harmonics (signal)-to-noise-ratio (SNR/HNR) • harmonic/noise amplitude •  HNR • Relatively more signal • Indicative of a normality •  HNR • Relatively more noise • Indicative of disorder • Normative values depend on method of calculation • “normal” HNR ~ 15

39. Harmonic peak Noise ‘floor’ Amplitude Harmonic peak Noise ‘floor’ Frequency

40. First harmonic amplitude From Hillenbrand et al. (1996)

41. Prominent Cepstral Peak

42. Spectral Tilt: Voice Source

43. Spectral Tilt: Radiated Sound

44. Peak/average amplitude ratio

45. From Hillenbrand et al. (1996)

46. WMU Graduate Students

47. Tense/Pressed/Effortful/Strained Voice Perceptual Description • Sense of effort in production Physiologic Factors • Longer closed phase • Reduced airflow Potential Acoustic consequences • Change in harmonic (periodic) energy • Flatter harmonic roll off

48. Spectral Tilt Pressed Breathy

49. Acoustic Basis of Vocal Effort Perception of Effort F0 + RMS + Open Quotient Tasko, Parker & Hillenbrand (2008)