Hermann Von Helmholtz
Physiology and sensation of hearing
Acoustics of speech (resonant frequencies of vocal tract)
Henry Sweet
Descriptive phonetics
May have been first to state concept between phonemic and allophonic contrast
Alexander Graham Bell
Teacher of the deaf
Father invented "visible speech
R.H. Stetson
Airflow, air pressure, articulation measurement, palatography
Homer W. Dudley
Speech synthesis
VODER
Haskin's Group
Franklin Cooper, Alvin Liberman, Pierce Delattre
Pattern playback machine
MKS
Meters, kilograms, seconds
CGS
Centimeters, grams, seconds
Pascal
Unit of pressure measurement
Newtons per meter squared
Dyne
Pressure required to move one gram one cm in one second
Pressure
Measured by the amount of water it displaces
cmH2O
Airflow
Volume traveled over time (l/min or ml/s)
Laminar flow
Molecules are not disrupted
Inverse
Relationship between pressure and volume
Boyle's Law
When the volume of an enclosed space decreases, pressure increases
How sound is created by changes in air pressure
Disturbances in air can create patterns of compression and rarefaction; these pressure changes travel away from the source of the disturbance in the form of sound waves
Elasticity (Hooke's Law)
Restores air molecules back to resting position in proportion to their distance of displacement
Inertia
Leads to an "overshoot" which is eventually overcome by elasticity again
Amplitude
Distance of displacement
Damping
The eventual decrease in amplitude that will lead molecules to settle into their original resting positions
Wave Motion
Areas of compression and rarefaction travel over distances in waves
Waveform
Amplitude - shown vertically
Time - shown horizontally
Periodic sound
Contains a repeating pattern of compression and rarefaction
Pure tone
Simple periodic sound with only one frequency
Complex Periodic Sound
Has multiple frequencies
Can only be periodic if the frequencies are at integer multiples
Fundamental Frequency
The component with the lowest frequency in complex periodic sound (Fo)
Harmonics
The other frequencies in a complex periodic sound
Occur at whole number multiples of Fo
Aperiodic
A wave in which individual cycles do not take the same amount of time to occur
Fourier
Mathematician who developed the process of showing how complex waves can be separated into separate frequencies
Spectra
Frequency - shown horizontally
Time - shown vertically
Advantage - easy to see how each component frequency results in the spectrum
Disadvantage - difficult to see how the sound changes over time
Pitch
Measured in mels
Perceptual correlate of Fo
Frequency
Measured in Hz or cps
The rate at which a repeating pattern occurs
Factors affecting frequency and pitch
The length, mass, and tension or an object determine its vibratory rate affecting frequency and pitch
Relationship between amplitude, intensity, and loudness
Amplitude and intensity are both physical measurements; they are both positively related but intensity increases at a faster rate
Loudness increases more slowly than amplitude and much more slowly than intensity
Bandwidth
The range of frequencies within a resonant area
Tools for measuring Fo in a clinical setting
Visi-Pitch
Praat
WASP
Vocal Range Profile
Graph that plots a person's phonational range against his/her dynamic range
Ataxic Dysphonia
Reduced Fo range w/ bursts of loudness
Spastic Dysphonia
Reduced range w/ low pitch
Wavelength
The physical size of a compression/rarefaction pattern in the air
Intensity
A measure of power generated
Loudness
Perceptual correlate of intensity and amplitude