Speech Breathing, Voice Science, Sound Waves, and Vowel Acoustics

Vocabulary flashcards covering respiration mechanics, laryngeal anatomy, voice measurement, acoustic theory, and vowel kinematics based on speech and hearing science lecture notes.

Open Quotient

An aerodynamic parameter defined as the ratio of the glottal open duration to the total period duration: $\frac{t_4 - t_1}{T_0}$.

Speed Quotient

An aerodynamic parameter defined as the ratio of the glottal opening phase to the glottal closing phase: $\frac{t_2 - t_1}{t_4 - t_2}$.

Stroboscopy

A clinical diagnostic technique that synchronizes flashing xenon light to the rate of vocal fold vibration to create the optical illusion of slowed motion.

Electroglottography (EGG)

A diagnostic technique that places two electrodes on the neck to pass a high-frequency electrical current, tracking cycle-to-cycle relative vocal fold contact area.

Source-Filter Theory

A model of speech production establishing that a sound source (such as vocal fold vibration or turbulence) is filtered and modified by the frequency-dependent resonances of the vocal tract.

Spectral Roll-Off

The rate of amplitude reduction across higher harmonics in the glottal source spectrum, characterized by a decrease of approximately $12\,\text{dB}$ per octave increase in frequency.

Formant

A concentration of acoustic energy around a resonant frequency of the vocal tract, visualized as an amplitude peak in the spectral envelope.

Quarter-Wave Resonator Formula

The formula calculating resonant frequencies ($F_n$) for a uniform tube open at one end and closed at the other: $F_n = (2n - 1) \times \left(\frac{c}{4L}\right)$, where $c$ is sound velocity ($34{,}000\,\text{cm/s}$) and $L$ is vocal tract length.

Acoustic Node

A location within a standing sound wave of a tube resonator characterized by minimum volume velocity and maximum pressure; constriction at this point raises formant frequencies.

Acoustic Antinode

A location within a standing sound wave of a tube resonator characterized by maximum volume velocity and minimum pressure; constriction at this point lowers formant frequencies.

Vocal Tract Transfer Function Across Speakers

An acoustic comparison demonstrating that shorter vocal tract lengths produce higher formant frequencies ($F_1$, $F_2$, $F_3$), as shown by the resonant values of a child ($9\,\text{cm}$), woman ($13\,\text{cm}$), and man ($17.5\,\text{cm}$).

Vowel Space Acoustic Chart

A two-dimensional acoustic representation displaying the physiological and acoustic range of the tongue during vowel production by plotting $F_2$ frequency on the x-axis against $F_1$ frequency on the y-axis.

Corner Vowel Formant Frequencies

Measured formant values for corner vowels demonstrating that /a/ has $F_1 = 1039\,\text{Hz}$ and $F_2 = 1506\,\text{Hz}$, /i/ has $F_1 = 291\,\text{Hz}$ and $F_2 = 870\,\text{Hz}$, and /u/ has $F_1 = 349\,\text{Hz}$ and $F_2 = 1048\,\text{Hz}$.

Onglide

The acoustic starting frequency and initial articulatory posture of a diphthong before the vocal tract begins transitioning.

Offglide

The acoustic ending frequency and target articulatory configuration reached at the termination of a diphthong.

Formant Transition

The dynamic acoustic trajectory between vowels or within a diphthong, characterized by transition duration, extent of frequency change, and slope (extent divided by duration).

jitter

• short-term frequency perturbation 

  • Short-term: one cycle to the next cycle

  • Cycle-to-cycle variability in 

  • non -volitional variability in F0

shimmer

• cycle-to-cycle variability of the intensity/amplitude of the acoustic waveform

  • Height is constant - no shimmer

  • If height amplitude fluctuates - there is shimmer

  • Cycle-to-cycle variability in amplitude of the acoustic waveform, which can affect vocal quality and perceived loudness.

Periodicity

• Vocal fold vibration is close to periodic 

• Classification of voice type

  • Type 1: nearly periodic

  • Type 2: fair amount of turbulence

  • Type 3: chaotic

• If successive cycles do not have the same period, it may relate to pathology 

  • Changes in vocal folds, laryngeal mechanisms, etc. 

Perturbation

• variability or irregularity in a system

Perturbation measures 

• Human voice is a nearly periodic signal

  • Have a little amount of jitter and shimmer, not zero

  • No perturbation at all would sound robotic and artificial 

• Harmonic energy: periodic parts

• Noise: all the rest

• Noise measures

  • Harmonic-to-noise ratio

  • Higher the better

  • May relate to voice quality

What is perturbation like?

• Jitter: Frequency perturbation

• Shimmer: Intensity perturbation

• Hoarse voices have higher jitter and shimmer

• Absence of perturbation

Phonatory Aerodynamics

• Evaluate glottal closure

• What is the importance of glottal closure