SHS 301 Exam 1
How/what are the characteristics of producing silibant fricatives How does the source and filter tie into the production of fricatives? F1/F2 range Place of articulation
Alveolar fricatives: ---Tongue forms constriction at alveolar ridge ---Air flows through midline groove of tongue against teeth ---Short anterior cavity emphasizes high frequencies Postalveolar fricatives: ---Tongue forms groove in alveopalatal region ---Lips are often rounded ---Longer anterior cavity emphasizes lower frequencies Frication (noise) stronger than in non-sibilants
What is damping?
Amplitude decreases over time as energy is lost to friction: ---damping
Fourier analysis
Any waveform can be analyzed or broken down into a series of sinusoids, each with a specific frequency, amplitude and phase A spectrum is calculated by performing Fourier analysis. waveform--Fourier Analysis-->amplitude & time spectra
Characteristics of fricatives F1/F2 range Place of articulation
Aperiodic sound source in upper vocal tract ----Airflow forced through constriction creates turbulence Can be formed at many places in vocal tract; in English: ---Labiodental [f v] ---Linguadental [Ө ð] ---Alveolar [s z] ---Postalveolar [∫ Ʒ ] May be voiced or voiceless
Relationship between loudness and phon.
At a given intensity, loudness perception varies with sound frequency. The unit of equal loudness is the phon. Different frequency with the same loudness are perceived as differently loud.
How does the CT contribute to longitudinal tension control?
Attachments: --Cricoid ring (anterior and lateral margins) --Thyroid cartilage (inferior edge) Contraction tilts the posterior lamina of the cricoid backward from the top: --The arytenoids, riding atop the cricoid, also tilt backward --The vocal folds are stretched (tension increases)
As the tine of a vibrating tuning fork moves away from its rest position, which force increases? A) Inertia B) Elasticity
B) Elasticity
A 100 HZ pure tone has shorter wavelengths and periods comparted to a 1000 Hz pure tone. A) True B) False
B) False
In the air, speed of sound is independent form the temperature. A)True B)False
B) False
Breathy voice is cased by A) irregularities in laryngeal tissues B) Incomplete vocal fold adduction C) Lesions produced by impact of vocal folds during phonation D) Extreme adduction
B) Incomplete vocal fold adduction Sound is aperiodic. Source is not properly vibrating
What is the fundamental frequency (fO) of the waveform in Hz A)100 B)125 C)1000 D)1250
B)125 1/0.008
What is the lowest frequency of resonance of a tube which is .7 m long, open at both ends? A)485.6 B)242.8 C)24.28 D)48.56 F= 340/(2 x 0.7)m
B)242.8
Which of the following cartilages are paired. A)Cricoid B)Arytenoid C)Thyroid D)All of the above D)None of the above
B)Arytenoid Smaller movement. Move for adjustment to the pitch. To tune it.
Consider the normal inhalation process A. Air entering the lungs causes the lungs to expand B. Expansion of the lungs causes air to enter the lungs C. Either a. or b. generally occurs depending on the initital air pressure within the lungs
B. Expansion of the lungs causes air to enter the lungs
The major muscle of inhalation is the: A. pectoralis major B. diaphragm C. Rectus abdominus D. External intercostals E. Serratus anterior
B. diaphragm
Half wave resonators: Is this an open or closed pipe? Know the formula and how to use it
Both open and closed. Wavelength = 2L L 2L/3 L/2 frequency= c/2L c/L 3c/2L 2C/L
How are different voice qualities produced?
By adjusting the glottal aperture, tension, and sub glottal pressure.
Which of the following statemnts is not correct? A) Longer vocal folds vibrate at lower frequencies B) Less massive vocal folds viaate at higher frequencies C) Tense vocal folds vibrate at lower frequencies.
C) Tense vocal folds vibrate at lower frequencies.
If the following components were combined: 240 Hz, 600 Hz, and 780 Hz, what would be the fundamental frequency A)40 B)50 C)60 maximum common denominator D)80
C)60 maximum common denominator
Which of the following functions is not of the larynx: A. Controls airflow in and out of lungs B. Protects pathway to lungs during swallowing. C. Decreases intrathoracic pressure during exertion, coughing. D. Provides sound source for speech
C. Decreases intrathoracic pressure during exertion, coughing.
Increasing subglottal pressure (Ps) does not yield an increase in A. intensity B. Fundamental frequency C. Lung volume D. Syllabic duration
C. Lung volume
How does resonance relate to the location of air particles and velocity relative to wavelength?
Closed end (glottis) --Air pressure is at a maximum. --Air particle velocity must approach zero. Open end (lips) --Air pressure is at a minimum. --Air particle velocity must be at maximum. Constricting the vocal tract near a pressure maximum (minimal velocity): --Raises the formant value. Why? -------Reduce L -> decrease l -> Increase f --Example: a constriction in the lower pharynx raises R1(or F1) Constricting near a region of minimum pressure (velocity maximum): --Lowers the formant value. Why? -----Increase L -> increase l -> decrease f --Example: a constriction at the lips lowers R2 (or F2)
Quarter wave resonators Is this an open or closed pipe? Know the formula and how to use it
Closed on one end, open on the other wavelength: 4L 4L/3 4L/5 4L/7 Frequency: v/4L 3v/4l 5v/4l 7v/4l
Characteristics of stops
Complete articulatory closure in oral cavity VP port closed Intraoral pressure (Pio) rises during closure Pio drops at release (vented through mouth unless following stop is nasally released, as in "hidden" [hIdn]) Oral release yields a transient noise source, also called a release-burst
What is language?
Complex rule-governed communication system that is specific to a given language:
Understanding simple waves provides a foundation for describing what?
Complex sounds.
What are the different observational domains of speech?
**Begins in CNS and ends in CNS** Neural processes -> neuromuscular process -> articulation -> acoustics -> hearing system -> stimulus transform -> neural processes
Muscles involved in vocal fold adduction
*Interarytenoid muscles* -Attachments: left and right arytenoid cartilages: ----Transverse IA runs horizontally between arytenoids ----Oblique IA connects arytenoids in X-shape -Draw arytenoids together posteriorly and adduct vocal folds *Lateral cricoarytenoid (LCA) muscles* -Attachments: ----Muscular processes of arytenoid cartilages ----Lateral margins of cricoid cartilage -Draw arytenoids forward and down -Assist in adduction
Observation Domain 6: Stimulus transformation
*Stimulus transformation* (psychoacoustics, psycho-phonetics, *speech perception*) What are the acoustic properties that keep vowels and consonants, monophthongs and diphthongs, stops and fricatives, voiced and voiceless consonants apart? The "same sound" is *acoustically different* when it is produced by different speakers - *very different* if the speakers are men vs. women vs. children. Why do they sound the same? The "same sound" is acoustically different when it is produced in different contexts.
What are the different types of pleura? Where are they located?
---Costal (rib) pleura (part of parietal) lines rib cage ---Pulmonary (visceral) pleura surrounds lungs ---Fluid holds the pleural layers together but allows sliding movement ---Lungs are pulled along as rib cage and diaphragm move
What vocal fold characteristics contribute to F0?
-Longer vocal folds vibrate at lower frequencies -Tense vocal folds vibrate at higher frequencies -Less massive (thinner) vocal folds vibrate at higher frequencies The cricothyroid (CT) muscle stretches and thins the vocal folds and increases f0
What are the components of the speech chain?
1) A message encoded in language and expressed phonetically (through the medium of sound) 2) Which means that a speaker is active, an acoustic signal is produced 3) and it is assumed that the spark is talking to someone (i.e. a hearer receives and processes the signal [decodes the message]
How many oscillations per second must there be to make sound?
20 oscillations per second
What is the range of hearing for a young healthy adults? What are the range of frequencies most important for perceiving speech? Frequencies produced in speech correspond fairly well to what?
20-20,000 Hz 100-5000 Hz with human auditory sensitivity
Higher resonances occur at odd-integer multiples of 1/4 wavelength. What would R2 and R3 be?
3/4 wavelength 5/4 wavelength
Hearing a complex sound composed of 600 + 900 Hz yields the pitch perception of a ______-Hz tone.
300 hz
What is the constant of speed of sound (the number)
344 m/s
Find the frequency and period: λ = 225 m λ = 170 m. λ = 507 m
344/225m = 1.52 hz 344/170m = 2.02 hz 344/ 507 m = 0.67 Hz 225m/344 m/s= .67 170/344 = .5 507/1.5 = 1.5
Define pleura.
A delicate membrane that encloses the lungs. The pleura is divided into two areas separated by fluid-the visceral pleura, which covers the lungs, and the parietal pleura, which lines the chest wall and covers the diaphragm. ---Costal (rib) pleura (part of parietal) lines rib cage ---Pulmonary (visceral) pleura surrounds lungs ---Fluid holds the pleural layers together but allows sliding movement ---Lungs are pulled along as rib cage and diaphragm move
Explain noise in regards to independence of filter from speech?
A noise source (frication) will show the same resonances as a periodic source as long as it is produced at the glottis (= glottal frication). This explains why we can hear vowels even when someone is whispering. Any other noise source (e.g. [x], [S], [s]) will only stimulate resonances in the cavity between the place of the noise source and the lips.
What are the essential constituents of sound?
A source of energy sets the source into motion. The vibrating source creates a disturbance. A medium (e.g., air, water) transmits the disturbance. If the disturbance is audible, there is sound.
The period is the time for a wave to complete a full cycle? A) True B) False
A) True
What is the lowest frequency of resonance of a tube open at one end and closed at the other and which is 5cm long? A)1700hz B)17hz C)3400hz D)34hz F= 340/ (4 x 0.05) m
A)1700hz
Which of the following is the major muscle in vocal fold lengthening? A.Cricothyroid B. Vocalis C. Lateral cricoarytenoid D. Posterior cricoarytenoid E. Oblique interarytenoid
A)Cricothyroid Changes the length of the vocal fold.
A 1000 Hz pure tone has shorter wavelengths and periods compared to a 100 Hz pure tone. A)True B)False
A)True
How do vocal folds adjust during speech?
Abduction: folds separated for voiceless sounds and breathing (rest position) Adduction: folds brought together for phonation (voiced sounds) Positions intermediate between full abduction or adduction may be used for some speech sounds
Active respiration: Related to resting volume
Above resting volume: ---Muscles counteract passive collapse of respiratory system ---Inspiratory muscles maintain lungs in expanded state ---Slow expiration early during exhalation phase Below resting volume: ---Muscles force respiratory system into compressed state ---Expiratory muscles compress thorax and abdomen ---Maintain expiration longer
What is fourier synthesis
Adding sinusoidal components together to get a complex signal
What happens when you add two waves out of phase? In Phase?
Addition of waves out of phase yields cancellation (destructive interference). Addition of waves in phase yields higher amplitudes (constructive interference).
What are the acoustic characteristics of affricates?
Affricates consist of a stop released into a fricative Affricates in English: [t∫ dƷ] Acoustics of affricates show features of both stops and affricates: ---Silent/voiced closure region ---Release burst ---Frication noise
How can the vocal tract be thought of as a tube?
Region between glottis and lips can be modeled as a tube that is open at one end, closed at the other Glottis (with adducted vocal folds) is the closed end Lips (separated for vowel production) form the open end
How do vowels compare across speakers? What is relative and what is absolute? Women/men/children Relative versus exact values?
Relative patterns of formant values are consistent across speakers; for example, [i] has a low F1, and a high F2. Absolute formant values vary across speakers: --Speakers differ in overall vocal-tract length. --Parts of the vocal tract may differ in size: The pharynx is proportionally smaller in women than men. Smaller in children than both men and women --Speakers of the same language vary in dialect and idiolect.
Total lung capacity + which of the following equals vital capacity A) B) C) residual volume D)
Residual Volume
How does vowel production change in clinical populations?
Congenitally deaf speakers often have deviant vowel spaces: --Jaw and tongue placements are more constrained than in hearing speakers. --The range of formant values is not as great as in hearing speakers. Impaired vowel production may be evident in apraxia of speech, dysarthria, and cerebral palsy --Dysarthria can occur disorders such as Parkinson's disease, multiple sclerosis Foreign accents may involve errors in vowel production Visual feedback (e.g., via spectrograms) may help speakers improve vowel production
Functions of the larynx
Controls airflow in and out of lungs Protects pathway to lungs during swallowing (especially in humans: larynx is just anterior to esophagus) Increases intrathoracic pressure during exertion, coughing, etc. Provides sound source for speech
How do we obtain sustained oscillations?
Convergent shape: bottom of vocal folds further apart than the top, i.e. air flow is converging. Divergent shape: bottom of the vocal folds are closer together. Air pressure is larger in convergent shape than in divergent shape. Asymmetry of air pressure is needed to sustain oscillation.
Cover model body of vocal folds
Cover: mostly mucous membrane (pliable) Body: mostly muscle (stiff) Body and cover have different vibratory properties Intrinsic laryngeal muscles determine how tightly the body and cover are connected in phonation
How do vocal folds typically move?
Cycle of vocal fold vibration Elastic recoil and Bernoulli effect
What is the fundamental period (To) of the waveform in seconds. Wave length = 2.75. A) .005 B) .05 C) .01 D) .008 period for the time of the waveform to restart itself
D) .008 period for the time of the waveform to restart itself
What is the wavelength of a sound that has a frequency of 120 Hz? Assume the speed of sound is 340m/s Hint: 100cm = 1 m A)4.08 B)408 C)28.3 D)283 cm
D)283 cm
internal intercostal muscles
Deep to external intercostals Run downward away from sternum Connect both osseous and cartilaginous portions of ribs: ---Interosseous portions: lower and compress rib cage: exhalation ---Interchondral portions: raise and expand rib cage: inhalation
How will the quarter wave resonator affect the phase and the resonances?
Difference between waves in free air and pipe: at the ends of pipe, whether open or closed, there are discontinuities that cause the sound to be reflected back into pipe, where the summation of incident (forward) and reflected (backward) waves creates a standing wave.
What do the different observation domains provide us in regards to communication?
Different perspectives on what people do to communicate
Muscle movements and activation during speech and how that relates to volume
During breathing, both inspiratory and expiratory muscles are active most of the time The balance between inspiratory and expiratory muscle action changes continuously The respiratory system maintains fairly constant pressure during speech Small variations occur to change intensity (e.g., for stressed syllables)
Global information about neural activity: EEG and MEG provide high what and where? MRI shows activity where and which low what? Can you get the clear picture from a single observation?
EEG and MEG provide high *temporal* resolution of activity in *small areas* of the brain. MRI shows activity in *all areas* of the brain but with low temporal resolution. Nothing is clear from *one* observation (noisy signals). Patterns emerge from the average of many repetitions.
Observation Domain 2: Neuromuscular processes What method is employed to observe and register what happens at this stage? What does it help you identify?
EMG (electromygraphy) Muscles responsible for the production of a particular event.
What are important structures of the thoracic cavity?
Encircled by bone (ribs, sternum, vertebrae) Diaphragm (sheet of muscle) forms floor Pleural linkage connects lungs to rib cage & diaphragm:
How will the quarter wave resonator effect the harmonics?
Every odd number, no even?
What are the muscles of respiration?
External intercostal muscles Internal intercostal muscles
For F0, what is the mathematical relation between higher harmonics?
F0 = H1 = 100 Hz H2 = 2(100 Hz) = 200 Hz H3 = 3(100 Hz) = 300 Hz H4 = 4(100 Hz) = 400 Hz, etc.
The amount of force applied to a vibrating body determines the frequency of vibration? A) True B) False
False
What are Filters in regards to sound?
Filters are used to select the part of a spectrum that I want to save or delete. Both our voice and hearing system are working as filters.
Know how to solve for Rx of a vocal tract with a given length: Solving for R1: Length of mans vocal tract is 17 cm
First (lowest) resonance (R1 or F1) occurs when tube length is equal to one-quarter l (wavelength of the sound source) Given: average vocal-tract length (L) of 17 cm First resonant frequency occurs when L = 1/4 l Solve for l : l = 4L = 4(17cm) = 68 cm 344000 cm/sec/68 cm = 506Hz
Explain: F1 varies with pharyngeal cavity size & mouth opening
High F1: small pharynx, open mouth, as for [a] Low F1: large pharynx, closed mouth, as for [i]
Explain this: F1 varies with pharyngeal cavity size & mouth opening
High F1: small pharynx, open mouth, as for [a] Low F1: large pharynx, closed mouth, as for [i] Large pharynx and closed mouth does a lower f1. Small pharynx and open mouth is generating a higher f1.
Explain this: F2 varies mostly with oral cavity length
High F2: short oral cavity, as for [i] Low F2: long oral cavity, as for [u]
Explain: F2 varies mostly with oral cavity length
High F2: short oral cavity, as for [i] Low F2: long oral cavity, as for [u]
Harmonics near formant frequencies resonate, and have high or lower amplitudes? Harmonics far from formant frequencies are high or lower?
High amplitudes Lower amplitudes
Tell me about the production of [i] High, mid, low Front, central, back Muscle involved Cavity shape F1 F2
High vowel: tongue body is elevated into the oral cavity, leaving pharynx open Front vowel: high point of the tongue is anterior, behind the alveolar ridge Genioglossus muscle is active to draw tongue up and forward Cavity shapes: large pharynx, small oral cavity F1 (back or pharyngeal cavity resonance) is low F2 (front or oral cavity resonance) is high
Tell me about the production of [u] High, mid, low Front, central, back Muscle involved Cavity shape F1 F2
High vowel: tongue is raised out of pharynx Back vowel: tongue dorsum is raised and retracted toward velum Rounded vowel: lips are rounded and protruded Styloglossus muscle is active to raise and back tongue Orbicularis oris muscle is active to round lips Cavity shapes: large pharynx, large oral cavity, overall vocal tract lengthened by lip protrusion F1 is low F2 is low
How can obstruents be affected in clinical populations?
Hyponasality or hypernasality may result from problems with velopharyngeal (VP) control: ---Cleft palate ---Motor speech disorders Poor control of VP mechanism may impair production of oral obstruents that require buildup of intraoral air pressure Problems of interarticulator timing in motor speech disorders may affect VOT and stop voicing contrasts
What is the missing fundamental frequency?
If the lower harmonics are not produced because of the poor fidelity or filtering of the sound reproduction equipment, you still hear the tone as having the pitch of the non-existent fundamental because of the presence of these beat frequencies. This is called the missing fundamental effect.
How does language relate to the speech chain?
In order for their to be speech, there must be a message. The message is the information the speaker conveys to the listener.
How does intensity relate to vocal fold vibration?
Increasing subglottal pressure increases voice intensity: --Vocal-folds are blown further apart; more air is released. Small changes in f0 also may result: ---Vocal-folds may become more tense. ---The Bernoulli effect is stronger. The glottal waveform has higher amplitude, shorter period, and faster closing.
In regards to SHM: what is inertia and elasticity/restoring forces?
Inertia and restoring forces (RF) vary continuously during cycle: ---RF is stronger when inertia is weak (when tines are more displaced) ---Inertia is strong when RF is weak (around rest position) Interplay between the two forces lets vibration persist Restoration can be elasticity, gravity, etc.
Explain speech breathing and phrasing
Inspirations usually occur at major linguistic boundaries (phrases, sentences) Long utterances require muscle control to maintain Ps throughout Utterance requirements affect both inspiratory and expiratory muscle use
What is sound?
Is a disturbance in a medium (like air) Produces a wave that travels through space The wave can be simple or complex ---Simple: one frequency only - a pure tone ---Complex: multiple frequencies - all other sounds, including speech
What cavities does the velum open/close? What speech sounds does this relate to?
It closes off or opens the nasal cavity nasal
Observation Domain 4: acoustic signal
It has a central position between speaker and hearer; it is the *output* of articulation and the *input* to the perception process. Different representations give us information about the distribution of acoustic energy in time or in frequency.
Constricting the vocal tract near a pressure maximum (minimal velocity) Does what to the formant value and why?
It raises the formant value. Reducing the length decreases the wavelength causing a higher frequency Constriction of the lower pharynx raises F1
How does a half wave resonator affect harmonics?
Its a full harmonic series of f, 2f, 3f, 4f.....
Inertia is what?
Kinetic
How/what are the characteristics of producing non-silibant fricatives How does the source and filter tie into the production of fricatives? F1/F2 range Place of articulation
Labiodental fricatives: ---Lower lip approximates upper incisors ---Orbicularis oris inferior active Lingua-dental fricatives: ---Tongue tip approximates upper incisors ---Superior longitudinal tongue muscle active Virtually no cavity anterior to constriction: ---Low-intensity frication (noise) ---Frication (noise) has a wide frequency bandwidth
Components of the laryngeal system (muscles and bones)
Larynx -Cartilages ---Thyroid, cricoid, arytenoid cartilages -Muscles ---Extrinsic & intrinsic laryngeal muscles -Attaches to trachea (below) and hyoid bone (above)
Explain Liquid and syllables
Liquids may function as syllable nuclei, e.g., [ledl] Production varies with syllable position in English: -[l] ----Syllable-initial: Tongue dorsum is low: Light /l/ ----Syllable-final: Tongue dorsum is high: Dark /l/ -[r] ----Syllable-final [r] is often coarticulated with the preceding vowel by raising the tongue tip
In regards to vocal cords, what varies across speakers?
Longer, more massive vocal folds yield lower fundamental frequencies lengthening the vocal folds increases the tension & decreases mass, leading to higher fundamental frequencies
Explain the compression and rarefaction in regards to longitudinal waves and transverse waves.
Longitudinal waves: There are areas of high pressure (*compression*) and areas of low pressure (*rarefraction*) In a sound wave the air molecules move forwards and backwards; where they are squashed together, a compression results, where they are forced further apart, there is a rarefaction. Transverse wave: Does not have compression and rarefaction but has peaks and troughs.
Tell me about the production of [a] High, mid, low Front, central, back Muscle involved Cavity shape F1 F2
Low vowel: jaw & tongue are lowered Back vowel: tongue is retracted into pharynx Anterior belly of digastric muscle is active to lower jaw Hyoglossus muscle is active to draw tongue down & back Cavity shapes: small pharyngeal cavity, large oral cavity F1 (back cavity resonance) is high F2 (front cavity resonance) is relatively low
Constricting near a region of minimum pressure (velocity maximum) does what to the formant value and why?
Lowers the formant value. Increase L -> increase wave length -> decrease f A constriction at the lips LOWERS R2
F0 common values for men, women, and children
Men: ~125 Hz Women: ~200 Hz Children: 300+ Hz
Explain breathing control during speech
More inspiration is used to control subglottal pressure Higher subglottal pressure -> louder sounds, higher pitch, longer duration.
Explain complex sounds of nature
Most noises in nature (e.g. wind blowing through branches or by ocean surf breaking at the shore) have no distinct frequency signature. They also carry very little useful information for us. What carries more information are _sudden changes in amplitude_ (a broken branch) or sounds with definite _frequency signature_ (animal call or insect buzz). Detecting changes in volume is rather easy, but recognizing frequency signatures is not.
Myoelastic aerodynamic theory
Myo-: muscles adduct vocal folds, establish levels of tension and elasticity Elasticity: allows vocal folds to stretch and return in each cycle Aerodynamic: subglottal pressure from the lungs drives vibration Physical (especially aerodynamic): forces set the vocal folds into motion in each cycle
Characteristics of nasals and how they relate to adjacent vowels What cavity is unique to nasals? What unique feature/murmur is unique to nasals? F1/F2 range Place of articulation
Nasals require open VP port (lowered velum): ---Levator palatini muscle is relaxed ---Palatoglossus muscle may actively lower velum ---Nasal cavities form a resonant chamber In nasal stops, the oral cavity is blocked at the same places of articulation as for the stops: ---At the lips [m] ---At the alveolar ridge [n] ---At the soft palate [ŋ] Opening the VP port creates a large resonant cavity: ---Results in low-frequency nasal resonance (c. 200-300 Hz) Amplitude is low: ---Antiresonances attenuate energy in some frequencies ---Large resonating space yields high damping ---Soft walls of nasal cavities absorb energy ---Acoustic radiation through nostrils is attenuated because of relatively small openings
Observation Domain 1: Neural Processes EEG and MEG provide high what and where? MRI shows activity where and which low what?
Neural processes (production and perception) - -EEG, MEG, MRI
Is breathing during utterances the same as breathing to live?
No
Glottal fricative /h/
No supraglottal constriction Usually involves turbulent noise at the glottis May be voiced, especially preceding stressed syllables (e.g., "behave") Vocal tract shape depends on following vowel
Is the glottal signal a sinusoid? If not what is it?
No, it is not energy at a single frequency. When the vocal folds vibrate and come together, they produce an impulse with harmonic energy. these "harmonics" are vibrations at every multiple of the fundamental glottal frequency.
Source & filter in [s]
Noise source at alveolar ridge; small anterior cavity Quarter-wave resonator between alveolar ridge and lips (analogous to vowels); L = ~1 cm Solving for resonant frequency with l = 4 cm: High frequencies emphasized for alveolar fricatives Lower frequencies emphasized for alveopalatal fricatives (longer front cavity; l increases)
Clinical applications of acoustics
Normal vocal-fold vibration is periodic; aperidocity may reflect vocal pathology. Speech acoustics reveal characteristics of articulatory movement. Acoustic analysis may reveal characteristics of speech that are not easily perceived auditorily.
Explain resonance in relationship to a standing wave.
One form of standing wave is resonance. Normally, if an object is excited to vibration, the vibration will fade away due to damping. However, all objects have a preferred vibration frequency called the resonance frequency, at which vibrations are reinforced as standing waves within the object. If not excited continuously, an object vibrating at resonance will eventually calm down, but over a longer period of time than it would take at any other frequency.
How is the vocal tract like a pipe?
Open on one end, closed on the other
What is an example of a half wave resonator?
Oral cavity
What are the muscular activity in stops?
Oral stops have closed VP port (levator palatini) Bilabial stops: Orbicularis oris used for lip closure (/p/ /b/) Alveolar stops: Superior longitudinal muscle elevates tongue tip (/t/ /d/) Velar stops: (/k/ /g/) ---Styglossus and palatoglossus muscles raise tongue dorsum ---Mylohyoid raises floor of oral cavity ---Contact is velar or palatal depending on vowel context Glottal stop: Vocal folds tightly approximated
Lip muscles
Orbicularis oris muscle encircles lips; used in: --Bilabial closures [p b m] --Lip rounding ([u] and [w]) Risorius muscle draws corners of lips back and up: --Active in lip spreading ([i])
How do peaks and troughs of a wave relate to compression/rarefraction?
Peaks are compression Troughs are rarefaction
What is the relationship between period and frequency? State the mathematical relationship.
Period: time (in seconds) to complete a cycle Frequency: cycles per second (Hz) Period & frequency are inversely related: ---If frequency = 20 Hz (20 cycles per second), then period = 1/20th of a second (50 ms) ---If frequency = 200 Hz, then period = 1/200th of a second (5 ms) Mathematically: --Frequency = 1/period --Period = 1/frequency T = 1/f
How is vocalization/periodicity related to the vocal folds?
Periodic: The pattern repeats every cycle Complex: Multiple frequencies are produced: f0 is the lowest frequency produced Voice pitch depends mostly on f0 Higher harmonics are whole-number multiples of f0 Intensity decreases as harmonic frequency increases If there is aperiodicity then it could cause vocal fry.
Explain subglottal and intraoral pressure
Phonation requires that Ps exceed pressure above vocal-folds by a threshold value Intraoral pressure buildup during consonants may cause phonation to cease (voiced stops)
Types of sound in speech production and their sources: Periodic Aperiodic
Phonatory source (periodic): air pressure forces the vocal folds to vibrate Supraglottal source (aperiodic): --Air pressure builds up behind vocal-tract closures & is released (stops) --Air is forced through narrow constrictions (fricatives) Lungs provide the air supply for both
What are the glottal states?
Plain voice Voiceless (or aspiration) Breathy voice Creaky voice (laryngealized) a) normal adduction ("modal voice") b) extreme adduction ("hard/pressed voice") c) weak adduction ("breathy voice")
Muscles involved in vocal fold abduction
Posterior cricoarytenoid muscles Attachments: --Arytenoid cartilages (muscular processes) --Dorsal plates of cricoid cartilages Rotate arytenoids and separate vocal folds
Acoustics of stop manner
Presence of a (near) silent interval during stop closure Rise-time (syllable-initial) or fall-time (syllable-final): Faster for stops than other consonants Presence of a release-burst F1 frequency: Rises for stops preceding vowels; falls for stops following vowels: ---Same principle as for vowels: Oral closure lowers F1 ---F1 transition extend depends on the F1 of adjacent vowels
Acoustics of intervocalic stop voicing
Presence or absence of closure voicing Closure duration longer for voiceless than for voiced stops Release burst (stronger for voiceless stops: intraoral pressure during closure is greater because the glottis is open)
What is Boyle's law and how does it related to respiration? How it relates to respiration
Pressure of a gas is inversely proportional to the volume Expansion of the chest and lungs creates negative pressure. (rarefaction) Air flows in to equalize the pressure (inhalation) Contraction of the chest and lungs creates positive pressure. Think of compression. Air flows out (exhalation) Exhaled airflow is modifie for speech production. Lowering and raising our diaphragm is what causes this pressure changes to allow breathing.
Glides [j] F1/F2 range Place of articulation
Production similar to [i]: --High, front tongue position --Genioglossus active Formant values similar to [i]: --Low F1 --High F2 Formant transitions vary depending on adjacent vowels
Glides [w] F1/F2 range Place of articulation
Production similar to [u]: --High, back tongue position, rounded lips --Styloglossus, orbicularis oris active Formant values similar to [u]: --Low F1 --Low F2 Formant transitions vary depending on adjacent vowels
Vocal tract what kind of resonator? Can this change?
Quarter wave resonator, closed on one end open on the other. When producing vowels or fricatives, think of it as closed at one end and open at the other. When producing stop-consonants, it is closed at both ends.
Is the outer ear a quarter or half wave resonator? How will this effect sound propagation?
Quarter wave resonator. Difference between waves in free air and pipe: at the ends of pipe, whether open or closed, there are discontinuities that cause the sound to be reflected back into pipe, where the summation of incident (forward) and reflected (backward) waves creates a standing wave. When a wave hits your ear canal, the air is sent back. Therefore we can resonate sound. (3kHz max sensitivity around here) The auditory canal in the external ear is about 25 mm long and behaves as a quarter wavelength resonator at about 3000 Hz. Therefore the human ear has its maximum sensitivity around this frequency
Calculate the resonance of the vocal tract (larynx to lips) if the length of the tube is 17 cm.
R1= 0.25 x 340 /0.17 = 500 Hz R2= 0.75 x 340/0.17 = 1500 Hz R3= 1.25 x 340/0.17 = 2500 Hz
How does larynx height contribute to F0?
Raised larynx: --Contraction of suprahyoid muscles --Tension may increase in the conus elasticus --f0 increases Lowered larynx: --Contraction of infrahyoid muscles (especially sternohyoid) --Tension may reduce in conus elasticus --f0 decreases
In which are the air molecules less close together? A) Rarefraction B) compression
Rarefraction
Are resonances harmonics? Why or why not?
Resonances are NOT harmonics. The greater the damping, the broader the maximum resonance area, but the less the difference between peak resonant energy and damped energy. In speech, we change the pitch of our speech to accentuate words, and to signal different types of sentence (e.g., final vs. non-final sentences). Such pitch movements change the value of the harmonics (as the fundamental pitch goes up, the harmonics move further apart) so a narrow filter might miss a harmonic altogether, and we would no longer have any energy being reflected.
What are the 3 major systems of speech production and their components?
Respiratory system -Lungs -Trachea -Rib cage -Thorax -Abdomen -Diaphragm Laryngeal system -Larynx -Vocal cords -Glottis Supralaryngeal system -Vocal tract -Articulators
What are the four areas of language?
Semantics Syntax Morphology Phonology
what acoustic properties will change resonances and how (i.e. shorter objects/lengths resonate at frequencies - etc.)
Shorter objects tend to vibrate at higher frequencies. Longer objects tend to vibrate at lower frequencies. Plucking a guitar string allows it to vibrate freely at its resonant frequency. Forcing a string to vibrate at a non-resonant frequency reduces its amplitude of movement. Bodies of air also have resonances. In speech, the vocal-folds vibrate freely, and the vocal-tract cavities undergo forced vibration.
Complex versus simple waveforms in regards to it being periodic.
Simple: one component, one frequency A pure tone Complex: Two or more component frequencies that are harmonically related: a fundamental frequency plus harmonics A complex tone
Define/know the cause and symptoms of Stuttering
Simultaneous contraction of abductor and adductor muscles may yield delayed phonation and a stuttering "block"
Independence of source and filter
Since resonances are a product of the vocal-tract shape, while the (periodic) excitation arises at the glottis, the two are independent of each other: Hold source constant while changing filter: ---Maintain constant pitch (f0) ---Vary vowel (e.g., change from [i] to [u]) Hold filter constant while changing source: ---Articulate a single vowel (e.g., [i]) ---Vary f0 (e.g., from low to high pitch) Source means i can modify the fundamental frequency without modifying the vocal tract. I can modify the type of vowel without modifying the intensity and the pitch. vocal tract is affecting the voice quality Source is affecting the pitch intensity
What is the velum? What muscles are involved in moving it?
Soft palate Contraction of levator palatini muscle raises velum: ---Closes the velopharyngeal (VP) port ---Separates nasal and pharyngeal cavities ---Used for oral speech sounds Relaxation of the levator palatini allows velum to drop: ---Opens the VP port ---Air flows freely into nasal cavity (as in breathing) ---Velum must be lowered for nasal speech sounds
How does the medium effect the speed of sound?
Sound velocity (c) in air is slower than in most media. Is independent of sound pressure and particle velocity Varies a little with air conditions (e.g., temperature), but is usually treated as a constant
How does a spring mass system relate to the vocal folds?
Spring ->tissue stiffness or restoring force in the vocal fold Mass ->vocal fold Damping -> viscosity (energy absorption) of the tissue When the bottom of the vocal folds are pushed together, the top opens, vice versa.
VOT Across languages?
Stop voicing contrasts differ across languages: --English (stressed, syllable-initial): ---/bdg/ usually short-lag VOT (negative VOTs may occur) ---/ptk/ long-lag VOT (voiceless aspirated) Spanish, Italian, French: ---/bdg/ have negative VOTs (voicing lead) ---/ptk/ short-lag VOT (voiceless unaspirated)
Explain how an open- end pipe affects nodes, phase, and particle velocities.
Sudden absence of confinement allows the emerging sound wave to expand into the surrounding air. Accompanied by sudden fall in sound pressure and an increase in particle velocity. Superposition of emerging wave and its reflection from the open creates a pressure node and a velocity antinode at the opening. Pressure phase is reverse but velocity phase is unchanged.
External intercostal muscles
Superficial Connect osseous portions of ribs Run downward toward sternum Raise and expand rib cage: inhalation
Tongue intrinsic muscles
Superior longitudinal: raises tongue tip, as for [l], "er" Inferior longitudinal: lowers tongue tip, as for [i] Vertical muscle: runs superior-inferior; flattens tongue body Transverse muscle: runs from left to right; narrows tongue body
Define/know the cause and symptoms of Alaryngeal speech
Surgical removal of larynx requires speaker to use other structures or a prosthesis for a sound source
How do tense versus lax vowels compare?
Tense vowels: e.g. [i e o u]: --Involve more extreme articulations --Have longer durations --Can occur in open syllables (e.g., CV) --May be diphthongized (e.g. [eI oU]) Lax vowels: [e.g., I ε ʌ ʊ] --Have less extreme articulatory postures --Are shorter in duration --Occur only in closed syllables (e.g., CVC)
What are resonating cavities in the vocal tract?
The Nasal and Oral Cavity
What does the speech chain define?
The broad area within which speech science asks its questions.
Pitch perception in aperiodic sounds usually reflect what?
The center of the frequency band, The frequency with the highest amplitude
Relationship between intensity and DB. Formula
The decibel measures the relative intensity between two sounds. db IL = 10(logsub10 Wo/Wr)
How is studying speech helpful?
The formulation of theories of speech (production and perception) The development of pronunciation-teaching methods and therapies for the speech impaired, heairng impaired Applications in speech and language technology
Breathing Control
The loudness of an utterance increases with increased airflow Changing airflow (volume-velocity) is the result of changing pressure within the lungs We control loudness in speech; therefore we modify the pressure and flow -- it is different from normal breathing to live After breathing in, the relaxation pressure is too high for the required loudness Inspiratory effort is necessary to reduce the excess pressure Different loudnesses require different lung pressures This means that for louder speech less time is needed to counteract the excess relation pressure EMG data show that muscles of inspiration are used to work against the excess relation pressure... ...and that active expiration takes over when relaxation pressure = required pressure
What is the lowest frequency of a complex sound?
The lowest frequency of a complex periodic sound is the fundamental frequency (f0) or first harmonic (H1): ----f0 Represents vibration along the whole length of the vibrating body.
What is the fourier transform?
The mathematical operation of fourier analysis is fourier transform. mathmatical operation that converts between time and frequency domain representations
What does the fundamental frequency represent in regards to someones voice?
The number of vocal-fold cycles per second
What are the characteristics of a simple harmonic motion?
The pattern of vibration repeats itself (it's periodic) Each cycle takes the same amount of time (the period is constant) Frequency (determined by period) is constant The graphic representation is a sine wave Tuning forks and pendulums (including swings) move in SHM
What is a node, what is an antinode?
The peaks of a standing wave are called antinodes and the points of zero displacement are called nodes.
What are the 3 features (and define them) that characterize consonants?
The place of articulation is where in the vocal tract the obstruction of the consonant occurs, and which speech organs are involved. The manner of articulation is how air escapes from the vocal tract when the consonant or approximant (vowel-like) sound is made The phonation of a consonant is how the vocal cords vibrate during the articulation. When the vocal cords vibrate fully, the consonant is called voiced; when they do not vibrate at all, it is voiceless.
How do dampened glottal cycles effect the speech signal?
The vocal tract is a very soft-walled cavity, so the air vibrations within it are quickly swallowed up, i.e. Energy gets absorbed. But also, whenever the glottis is open, energy gets lost back down into the trachea (windpipe). This is what is meant by the expression „highly damped" Each glottal closure brings fresh energy into the system. Different degrees of damping would affect the speech signal. High degree would cause the signal to almost die out.
What is the filter for speech? What is the source? How do they interact?
The vocal tract is the filter for speech The source of speech is the vibration of the vocal folds The source is filtered (modified) to produce different speech sounds. The resonator properties change according to the shape of the vocal tract.
How are frequency and wavelength related to each other?
They are inversely related to each other. Low frequencies Have longer wavelengths Travel well through barriers (e.g., walls) High frequencies Have shorter wavelengths Tend to reflect off barriers
Respiratory quantities: Tidal volume Vital capacity Relaxation volume Total lung capacity
Tidal volume: amount of air exchanged (in and out) during a cycle of quiet breathing Vital capacity (VC): amount of air exchanged in maximum inspiration-maximum expiration: ---Respiratory volumes often expressed as a percentage of VC (e.g., tidal volume is about 10% of VC) Resting volume: the respiratory system relaxes at about 40% of VC Total includes: vital (inspiratory and expiratory reserve), residual
What is voice onset time and what are its three categories?
Time between stop release and phonation onset. Voicing lead:voicing begins before stop release Short-lag:voicing begins at or very shortly after stop release Long-lag:voicing begins well after release
Glides [l], [r] F1/F2 range Place of articulation
Tongue-tip raised toward alveolar ridge (superior longitudinal muscle) [l]: Tongue-tip contact with alveolar ridge: --Sides of tongue down: Lateral emission of air [r]: No tongue-tip contact with alveolar ridge: --Often retroflexed (tongue tip bent back) --Often has lip rounding Acoustics of [l r] evident in F2 and especially F3: --F3 low for [r] --F3 level for [l]
Observation Domain 3: articulation production
Traditional observation domain in phonetics We can see what speaker are doing with their articulators here. For the ones we cant see, we can produce the sound and feel what we are doing.
What is the direction and propagation of a transverse wave and longitudinal wave relative to their source
Transverse wave displacement is perpendicular (90 degrees) to the direction of travel. (spring moving up and down) ---electromagnetic waves are transverse Longitudinal wave: displacement is parallel to direction of travel
Speed of sound waves in air (c) = 340 m/s. What is the fundamental frequency (1st harmonic) of an open-end air column which has a length of 67.5 cm? Given: c = 340 m/s, L = 67.5 cm or 0.675 m. What is f1 =?
Velocity (speed) = frequency x wavelength. Wavelength λ = 2 x L = 2 x 0.675 = 1.35 m Therefore, frequency = c / λ = (340 m/s) / (1.35 m) = 253 1/s = 253 Hz.
Determine the length of an open-air column required to produce a fundamental frequency (1st harmonic) of 480 Hz. The speed of sound (waves) in air is known to be 340 m/s. Given: v = 340 m/s, f1 = 480 Hz, L = ?
Velocity (speed) = frequency x wavelength. Wavelength λ = c / f1 = (340 m/s) / (480 Hz) Therefore, wavelength λ = 0.708 m. Length of column L = λ / 2 = 0.354 m
What are important structures for the respiratory system?
Vertebral column Sternum Ribs: --Join to vertebral column at back (bony connections) --Upper ribs join sternum at front via cartilage --Lower (floating) ribs connect to vertebrae only
Components of vocal folds
Vocal processes of arytenoid cartilages Vocal ligament (thickened edge of conus elasticus membrane) Thyroarytenoid muscle (includes vocalis muscle, along edge of glottis) Superficial mucous membrane
Define/know the cause and symptoms of Spasmodic dysphonia
Vocal-fold paralysis yields inability to initiate or maintain phonation; strangled voice quality
Respiration contours in clinical populations
Voice disorders: improper laryngeal valving may waste exhaled air Hearing impairment: poor laryngeal control may again waste air Motor speech disorders: may affect respiratory muscle coordination
What are the sound sources for consonants?
Voiced consonants (includes all sonorants): Periodic laryngeal source Voiceless consonants: --Supraglottal noise sources --Aperiodic laryngeal source: [h] noise, aspiration Obstruents: Supraglottal noise sources: --Stop bursts: Release built-up pressure; transient noise --Frication: Air forced through a narrow channel becomes turbulent; sustained noise Voiced obstruents combine periodic and aperiodic sources
How does VOT relate to articulation?
Voicing lead: --Vocal folds approximated throughout stop closure --Phonation occurs during stop closure Short-lag: --Vocal folds adducted by the time the stop is released --Silent closure; phonation begins at release or just after Long-lag: --Vocal folds adduct after the stop is released --Voicing is delayed; the stop is aspirated
Speed of sound is what in terms of wavelength and period?
Wavelength/period
If the glottal source remains the same and the filter changes (i.e. the vocal tract) how can that effect F0/ the speech sound?
We are figuring out how it is possible to distinguish a different vowel when the source is the same. You are changing the filter to get different pitches. Filtering of the vocal tract is called formant.
In regards to SHM: Displacement and velocity
When displacement is maximum (the swing is far out to the left or right): ---RF (restoring force) is strong, pushing the swing back downward ---Inertia is momentarily zero as the swing stops and reverses When displacement is zero: ---Inertia is strong: The fastest movement occurs as the swing passes the rest position. ---RF is momentarily zero as the swing passes through the rest position
Why cant we hear the frequency in nature?
When getting the frequency information, the most important aspect is the *repeating pattern of the movements* that distinguish sounds from the noises. A sound has a pitch, which is determined by the frequency with which the pattern repeats itself. Such a regular movement is described by a sine wave which has a particular frequency GUITAR STRING EXAMPLE
What are Standing waves?
When two waves collide that are identical in frequency and amplitude and traveling in opposite directions, they can create a standing wave. Unlike traveling waves, standing waves appear to vibrate in place. They remain in a constant position. The wave peaks alternate from positive to negative in place but do not move forwards or backwards, and each peak terminates with a point of zero displacement on both sides.
What is white noise?
White noise (e.g. 's' , 'shhh, 'zz') amplitude at any given time is random, but average spectral density is flat. It is called white noise because it consists of a full spectrum of waveform frequencies, similar to how white light is a combination of a full spectrum of visible colors
Can H1 be inferred if it is missing from the signal?
Yes.
Why isn't there a resonance produced for even numbered multiples (quarter wave resonator)
Yield opposing forces that interfere with the vibratory pattern
In regards to bernoulli effect: What does flow through the glottis cause in regards to pressure? Inward pressure helps with what?
Yields a pressure drop Inward pressure helps the close vocal folds in each cycle
high-pass filter
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By examining the phonetic events in relation to the message gives us what?
a lot of knowledge about the structure of speech insight into how the properties of speech affect the message
For stops the frequency range of most intense portion of release-burst is what for: • Alveolars • Bilabials • Velars
alveolar: ~3kHz bilabials: ~600Hz Velar: burst frequencies (and point of closure) depend on following vowel F2 transition to/from a following/preceding vowel ---as for vowels, F2 relates to tongue position in oral cavity ---F2 transition reflects placement of following vowel
What is a oscillation compared to vibration?
any back-forth movement. if force of elasticity involved, then the oscillation is vibration.
Noise at the glottis also can provide an _________ sound source for the vowels of speech>
aperiodic
Can periodic or aperiodic sound sources excite the resonances of vocal tract cavities?
both
Frequency is what?
cycles per second
What is wavelength?
distance between corresponding points in successive cycles of waves DISTANCE NEEDED FOR A WAVE TO COMPLETE A CYCLE
what is changed in regards to source and filter? same excitation,different resonance
filter changed source is constant
Define/know the cause and symptoms of Breathiness
incomplete vocal fold adduction
What is the amplitude of a wave?
initially depends on the amount of force used to start movement (A strong push makes a swing move further...a strong muscular push makes your voice stronger) Amplitude decreases over time as energy is lost to friction: ---damping
Define/know the cause and symptoms of Hoarseness?
irregularities in laryngeal tissues (e.g., swelling)
Define/know the cause and symptoms of Contact ulcers
lesions produced by impact of vocal folds during phonation (often reflects excess muscular tension)
How do our ears separate various frequencies?
on the principle of resonance
Explain how a closed end pipe affects nodes, phase, and particle velocities.
particle displacement and particle velocity are zero, standing wave has velocity zero, therefore it has a velocity node. Node created by reversal of the particle velocity at the reflection, reflected wave initiated with particle velocities in antiphase with those in the incident wave. Pressure phase is not reversed. Pressure is double that in the incident wave, pressure antinode.
Vocal-fold vibration usually provides a _________ sound source for vowels and voiced consonants.
periodic
What is the difference between periodic and aperiodic sounds?
periodic: pattern repeats itself aperiodic: pattern does not repeat itself
Elasticity is what?
potential Energy
What is velocity?
rate at which sound wave advances. In air, speed of sound is independent of frequency. But not in the case of waves travelling over water - speed is not independent of frequency. DISTANCE OVER TIME
What type of waveform does the glottal signal resemble?
sawtooth signal. The glottal waveform is a harmonically rich signal with energy in the whole frequency range important for speech. So, the glottal waveform supplies the acoustic energy needed for all the different (voiced) speech sounds. We call it the source for the speech signal To form different sounds, the energy has to be modified into different patterns; The basic shape of theglottal excitation is(more or less) constant. The most important fact about this type of wave is the presence of ALL the harmonics above the fundamental. This means that there is energy throughout the spectrum to modify into different speech (voiced) sounds.
What do higher harmonics reflect within the vibrating body?
shorter vibrating segments ---H2 represents vibration along 1/2 of the vibrating body; H3 is vibration along 1/3, etc.
Complex versus simple waveforms in regards to it being aperiodic.
simple: nada :P complex: Two or more component frequencies no harmonically related: no fundamental frequency, no harmonics...noise
What is changed in regards to source and filter? We have a different excitation but the same resonance
source changed, filter is constant
Tongue extrinsic muscles
styloglossus: up and back, as for [u] Hyoglossus: down and back, as for [A] ('father') Genioglossus: up and forward, as for [i] , [e] Palatoglossus: up
What is resonance in regards to the vocal tract?
the phenomenon whereby a body, which has a natural tendency to vibrate at a certain frequency (natural or resonant) can be set into vibration by another body whose frequency is v. similar or identical to the vibration of the first body The result of filtering the sound source passing through the supraglottal cavities of the vocal tract In speech, supraglottal cavities are shaped by the articulators Resonant frequencies determined partly by cavity size Resonances of the vocal tract are called formants
Observation Domain 5: auditory system Is there a 1:1 relationship between the acoustic signal and the sound patterns we perceive? Why must we understand this for speech?
the physiological and neurological foundation of perception Nope! There are modifications to the signal that take place on its way to the brain. any acoustic signal must pass through the same auditory system. Therefore, we need to know how the system affects the speech signal if we want to understand how speech is perceived.
What is resonance?
the tendency of a system to vibrate with increasing amplitudes at some frequencies of excitation
What is the period of a wave?
time to complete one cycle; it is constant for a given vibrating body
Waveform versus spectra: -What are the axes -What information does this graph display -How do you obtain a spectra from a waveform or a waveform from spectra?
x axis: frequency Y axis: amplitude Shows amplitude of each harmonic Shows a single time slice only: no time-varying information It is obtained by fourier analysis: analyzing complex waves into simple components (Complex periodic on spectra shows multiple different length lines, while pure tone shows one line) (complex periodic shows a curve)
band stop and band pass filter
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Low pass filter
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SHM: How does all this relate to a tuning fork?
|_| At Rest | /_\ In ward displacement. | |_| Back to rest position | (E decreases, I increases) \_/ outward displacement. | (E increases, I decreases) |_| Back At Rest | (E decreases, I increases) END OF ONE CYCLE
Calculate λ given f in a female speaker: f0 = 200 Hz c = 344 m/s
λ=c/f (344 m/s)/ 200 Hz = 1.72 m
What do these stand for? ω k f λ
ω is angular frequency k is wavelength constant, f is frequency λ is wavelength
Why is the acoustic tube needed for vocalizations?
For the vocal folds to sustain oscillation, we know there must be a negative pressure within the glottis. But, pressure from the lungs cannot be negative; it is always positive. SO we add the acoustic tube When the glottis is closing, the airflow begins to decrease, but the air that is above the glottis does not "know" this, so it continues to move with its same speed (because of inertia). This creates a region just above the vocal folds where the air pressure decreases, because air is not coming from the bottom through the glottis as fast as it is leaving above. Pressure builds up below the glottis, causing them to open. When the vocal folds are opening, fluid pressure against the walls is greater than when the vocal folds are close together. Thus, it is the asymmetry of driving force (air) that sustains oscillation. If there was no vocal tract, there would only be one puff of air, not a series of puffs.
What is the relationship between fourier synthesis and spectra?
Fourier synthesis takes the components of a spectrum and puts it into a waveform. waveform<--Fourier Synthesis--amplitude & time spectra
What are the formulas for velocity?
Frequency x wavelength 𝜆 x f (hz) Distance over time 𝜆/T c = ω λ/2π c= ω/k Where k = 2 π/λ and ω=2πf (k is called the phase change coefficient or wavelength constant. If the wave is "frozen" at an instant so that the particle displacement is seen as function of position, this coefficient is the rate at which phase changes with distance from the source) (Where ω, the angular frequency, is the rate of change of phase with time when vibrations are observed at a given place.)
Frequency vs pitch What is their relationship?
Frequency: a measurable characteristic of acoustic signals Pitch: a listener's perceptual response (mainly) to frequency Frequency & pitch are related: higher perceived pitch results (mostly) from higher frequency However: the relationship is nonlinear, especially at frequencies >1000 Hz
How do you find the fundamental frequency?
Fundamental frequency of a complex wave is the greatest common denominator of the frequencies of the component waves.
Define F0 and harmonics and know how to calculate and how they relate:
Fundamental frequency of a complex wave is the greatest common denominator of the frequencies of the component waves. ex: Fo of a complex wave with 400 Hz and 500 Hz compounds is 100 Hz.