2. Physiological and Acoustic Phonetics: A Speech Science Foundation

Question 1

Pitch

Answer 1

• Auditory sensation (i.e., perception) of the frequency with which the VFs vibrate, whereas frequency is a physical property of the actual sound waves
• Determined by mass, tension, and elasticity of the VFs
• Can affect meaning (e.g., statement vs question)

Question 2

Intensity

Answer 2

• Intensity is sound pressure
• Sensory correlate of intensity is loudness/volume
• Loudness is related to amplitude

Question 3

Juncture

Answer 3

“Vocal punctuation”

• Combination of suprasegmentals (e.g., intonation and pausing)
• E.g., “What did you eat?” vs “What, did you eat?”; “I scream” vs “Ice cream”

Question 4

Acoustics: Basic Definitions

Sound Waves

Answer 4

Movements of particles in a medium containing expansions and contractions of molecules; Waves can be periodic or aperiodic

Question 5

Compression (aka Condensation)

Answer 5

Compression/condensation: a phase of sound in which the vibratory movements of an object (e.g., the tines of a tuning fork) increase the density of air molecules b/c the molecules are compressed or condensed; Opposite of rarefaction

Question 6

Rarefaction

Answer 6

Thinning of air molecules when the vibrating object returns to equilibrium; Opposite of condensation

Question 7

Simple Harmonic Motion

Answer 7

Back-and-forth movement of particles when the movement is symmetrical and periodic; Aka a sine wave

Question 8

Sinusoidal Motion/Wave

Answer 8

A wave with horizontal and vertical symmetry b/c it contains one peak/crest and one valley/trough; Contains a single frequency and is a result of simple harmonic motion

Question 9

Amplitude

Answer 9

Amplitude is 1 of 2 characteristics of vibratory motion and is the magnitude and direction of displacement; In acoustics, it is the strength and magnitude of a sound signal (the greater the amplitude, the louder the sound signal)

Question 10

Intensity

Answer 10

Quality of sound that creates the sensation of loudness; Physically, intensity is the amount of energy transmitted per second over an area of one square meter; Measured in terms of watts per square meter and is also expressed in decibels (dB)

Question 11

Frequency

Answer 11

Frequency is 1 of 2 characteristics of vibratory motion; It is the rate of vibratory motion that is measured in terms of the number of cycles completed per second or, more recently, in terms of hertz (Hz)

Question 12

Natural Frequency

Answer 12

Frequency with which a source of sound normally vibrates; Determined by the source’s mass (quantity of matter) and stiffness

Increased mass results in decreased frequency, and increased stiffness results in increased frequency

Question 13

Formant Frequency and

Fundamental Frequency

Answer 13

Formant frequency: A frequency region with concentrated acoustic energy; It is the center frequency of a formant, which is a resonance

Fundamental frequency: lowest frequency of a periodic wave; It is the first harmonic

Question 14

Octave

Answer 14

Indication of the interval between two frequencies; The intervals always maintain a ratio of 1:2; thus, each octave doubles a particular frequency (e.g., 200 Hz is one octave above 100 Hz)

Question 15

Impedance

Answer 15

Acoustic, mechanical, or electrical resistance to motion or sound transmission

Question 16

Newton’s Law of Motion

Answer 16

Explains motion and its characteristics. Basically, sound involves motion. The law of inertia states that all bodies remain at rest or in a state of uniform motion unless another force acts in opposition. I.e., a body in motion tends to stay in motion and a body at rest tends to stay at rest. The law of reaction forces says that every force is associated with a reaction force of opposite direction

Question 17

(Sound) Pressure

Answer 17

Pressure is the amount of force per unit area

Force is measured either as dynes or as newtons and is important in understanding the amount of force sound waves exert on the eardrum

Question 18

Sound Wave Generation and Propagation

The 2 Main Properties of a Medium That Affect the Transmission of Sound

Answer 18

Mass (density) and Elasticity

*A more elastic medium (even if it is more dense) will propagate sound faster than a less elastic (even if it is less dense) medium (e.g., steel>air)

Question 19

Velocity

Answer 19

The amount of molecular displacement per unit of time is measured in terms of velocity ; A change in velocity is described as acceleration or deceleration; Acceleration is also related to direction of movement (when direction changes, velocity also changes)

Question 20

Frequency and Pitch: The normal ear of a young adult can respond to __ Hz to ___ Hz.

Answer 20

20 Hz to 20,000 Hz

Human ear is more sensitive to changes in lower frequencies (below 1,000 Hz) vs higher frequencies

Question 21

Intensity of normal conversational speech

Answer 21

Varies between 50 and 70 dB SPL

very intense sounds exceed 100 dB SPL and may induce pain