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Behrman Chapter 5, 6 Place less emphasis on… • Minor anatomical landmarks and features 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

Laryngeal Activity in Speech/Song • Sound source to excite the vocal tract – Voice Laryngeal Activity in Speech/Song • Sound source to excite the vocal tract – Voice – Whisper • Prosody – Fundamental frequency (F 0) variation – Amplitude variation • Realization of phonetic goals – – – Voicing Devoicing Glottal frication (/ /, / /) Glottal stop (/ /) Aspiration • Para-linguistic and extra-linguistic roles – Transmit affect – Speaker identity

The vocal fold through life… • Newborns – No layered structure of LP – The vocal fold through life… • 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 Glottal Cycle The Glottal Cycle

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

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

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

 • VF adducted & tensed → myoelastic pressure (Pme ) • Glottis is • VF adducted & tensed → myoelastic pressure (Pme ) • Glottis is closed • subglottal air pressure (Psg) ↑ • Psg ~ 8 -10 cm H 20, Psg > Pme • L and R M 1 separate • Transglottal airflow (Utg) = 0 As M 1 separates, M 2 follows due to mechanical coupling stiffness Psg > Pme glottis begins to open Psg > Patm therefore Utg > 0

Utg ↑ ↑ since glottal aperature << tracheal circumference Utg ↑ Ptg ↓ due Utg ↑ ↑ since glottal aperature << tracheal circumference Utg ↑ Ptg ↓ due to Bernoulli effect Pressure drop across the glottis Bernoulli’s Law P + ½ U 2 = K where P = air pressure = air density U = air velocity

Utg ↑ Ptg ↓ due to Bernoulli effect Plus “other” aerodynamic effects Ptg < Utg ↑ Ptg ↓ due to Bernoulli effect Plus “other” aerodynamic effects Ptg < Pme M 1 returns to midline M 2 follows M 1 due to mechanical coupling stiffness Utg = 0 Pattern repeats 100 -200 times a second

Limitations of this simple model Limitations of this simple model

The Glottal Cycle The Glottal Cycle

Instantaneous sound pressure Sound pressure wave Time Instantaneous sound pressure Sound pressure wave Time

Phonation is actually quasi-periodic • Complex Periodic – vocal fold oscillation • Aperiodic – 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

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

Measuring Glottal Behavior • Videolaryngoscopy – Stroboscopy – High speed video Measuring Glottal Behavior • Videolaryngoscopy – Stroboscopy – High speed video

illumination Photoglottography (PGG) Time illumination Photoglottography (PGG) Time

Electroglottography (EGG) • Human tissue = conductor • Air: conductor • Electrodes placed on 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

Electroglottogram Electroglottogram

Glottal Airflow (volume velocity) • Instantaneous airflow is measured as it leaves the mouth Glottal Airflow (volume velocity) • 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

Flow Glottogram Flow Glottogram

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

F 0 Control • Anatomical factors Males ↑ VF mass and length = ↓ F 0 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

Fundamental Frequency (F 0) Average F 0 • • speaking fundamental frequency (SFF) Correlate Fundamental Frequency (F 0) Average F 0 • • 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: F 0 ↓ Older males: F 0 ↑ F 0 variability • F 0 varies due to – Syllabic & emphatic stress – Syntactic and semantic factors – Phonetics factors (in some languages) • Provides a melody (prosody) • Measures – F 0 Standard deviation • ~2 -4 semitones for normal speakers – F 0 Range

Maximum Phonational Frequency Range • • • highest possible F 0 - lowest possible Maximum Phonational Frequency Range • • • highest possible F 0 - lowest possible F 0 Not a speech measured in Hz, semitones or octaves Males ~ 80 -700 Hz 1 Females ~135 -1000 Hz 1 3 octaves often considered normal 1 Baken (1987)

Fundamental Frequency (F 0) Control • Ways to measure F 0 – Time domain Fundamental Frequency (F 0) Control • Ways to measure F 0 – Time domain vs. frequency domain – Manual vs. automated measurement – Specific Approaches • • Peak picking Zero crossing Autocorrelation The cepstrum & cepstral analysis

Autocorrelation Data Correlation + 1. 0 + 0. 1 - 0. 82 + 0. Autocorrelation Data Correlation + 1. 0 + 0. 1 - 0. 82 + 0. 92

Cepstrum Cepstrum

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

Measuring Amplitude • Pressure • Intensity • Decibel Scale Measuring Amplitude • Pressure • Intensity • Decibel Scale

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

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

Vocal Quality • no clear acoustic correlates like pitch and loudness • However, terms Vocal Quality • 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

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

Breathiness Perceptual Description • Audible air escape in the voice Physiologic Factors • Diminished 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

harmonics (signal)-to-noise-ratio (SNR/HNR) • harmonic/noise amplitude • HNR – Relatively more signal – Indicative 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

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

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

Prominent Cepstral Peak Prominent Cepstral Peak

Spectral Tilt: Voice Source Spectral Tilt: Voice Source

Spectral Tilt: Radiated Sound Spectral Tilt: Radiated Sound

Peak/average amplitude ratio Peak/average amplitude ratio

From Hillenbrand et al. (1996) From Hillenbrand et al. (1996)

WMU Graduate Students WMU Graduate Students

Tense/Pressed/Effortful/Strained Voice Perceptual Description • Sense of effort in production Physiologic Factors • Longer 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

Spectral Tilt Pressed Breathy Spectral Tilt Pressed Breathy

Perception of Effort Acoustic Basis of Vocal Effort F 0 + RMS + Open Perception of Effort Acoustic Basis of Vocal Effort F 0 + RMS + Open Quotient Tasko, Parker & Hillenbrand (2008)

Roughness • Perceptual Description – Perceived cycle-to-cycle variability in voice • Physiologic Factors – Roughness • Perceptual Description – Perceived cycle-to-cycle variability in voice • Physiologic Factors – Vocal folds vibrate, but in an irregular way • Potential Acoustic Consequences – Cycle-to-cycle variations F 0 and amplitude – Elevated jitter – Elevated shimmer

Period/frequency & amplitude variability • Jitter: variability in the period of each successive cycle Period/frequency & amplitude variability • Jitter: variability in the period of each successive cycle of vibration • Shimmer: variability in the amplitude of each successive cycle of vibration …

Jitter and Shimmer Sources of jitter and shimmer • Small structural asymmetries of vocal Jitter and Shimmer Sources of jitter and shimmer • Small structural asymmetries of vocal folds • “material” on the vocal folds (e. g. mucus) • Biomechanical events, such as raising/lowering the larynx in the neck • Small variations in tracheal pressures • “Bodily” events – system noise Measuring jitter and shimmer • Variability in measurement approaches • Variability in how measures are reported • Jitter – Typically reported as % or msec – Normal ~ 0. 2 - 1% • Shimmer – Can be % or d. B – Norms not well established

Vocal Register What is a vocal register? Vocal Register What is a vocal register?

Vocal Registers Pulse (Glottal fry) – – – 30 -80 Hz, mean ~ 60 Vocal Registers Pulse (Glottal fry) – – – 30 -80 Hz, mean ~ 60 Hz Closed phase very long (90 % cycle) May see biphasic pattern of vibration (open, close a bit, open and close completely) Low subglottal pressure (2 cm water) Energy dies out over the course of a cycle so parts of the cycle has very little energy Hear each individual cycle

Vocal Registers Modal – – – VF are relatively short and thick Reduced VF Vocal Registers Modal – – – VF are relatively short and thick Reduced VF stiffness Large amplitude of vibration Possesses a clear closed phase The result is a voice that is relatively loud and low in pitch Average values cited refer to modal register

Vocal Registers Falsetto – – – – 500 -1100 Hz (275 -600 Hz males) Vocal Registers Falsetto – – – – 500 -1100 Hz (275 -600 Hz males) VF are relatively long and thin Increased VF stiffness Small amplitude of vibration Vibration less complex Incomplete closure (no closed phase) The result is a voice that is high in pitch