Chapter 2: Acoustics

Question 1

Acoustics

Answer 1

-study of sound

Question 2

Sound

Answer 2

-audible disturbance in a medium caused by a vibrating source

Question 3

Waves

Answer 3

-disturbances in the medium

Question 4

Where can sound waves exist?

Answer 4

-gas
-liquid
-solid
-these are all mediums

Question 5

Simple Harmonic Motion

Answer 5

-periodic or oscillation motion
-restoring force directly proportional to displacement and acts in direction opposite to that of the displacement

Question 6

Damping

Answer 6

-decrease in amplitude over time

Question 7

What medium is speech most often transmitted in?

Answer 7

-air
-speech can be transmitted in other mediums

Question 8

Obstacles of Sound Traveling through Air

Answer 8

-air particles not visible to human eye
-sound waves made up of complex patterns of air molecule disturbance

Question 9

Compression

Answer 9

-molecules are close together
-the top half of a complete cycle

Question 10

Rarefaction

Answer 10

-molecules are spread apart
-bottom half of complete cycle

Question 11

Wavelength

Answer 11

-distance from one area of compression to another

Question 12

Pure Tones

Answer 12

-one frequency
-not characteristic of speech
-simple harmonic motion (periodic): repeats itself in exactly the same way at a regular interval

Question 13

Complex Sounds

Answer 13

-multiple frequencies
-characteristic of speech
-periodic, aperiodic, and a mixture of both
-fundamental freq and overtones

Question 14

Cycle

Answer 14

-individual vibrations

Question 15

Frequency

Answer 15

-number of cycles per second
-measured in hertz

Question 16

Amplitude

Answer 16

-place of maximum displacement

Question 17

Period

Answer 17

-amount of time it takes to complete 1 full cycle
-one up and down

Question 18

Pressure Wave Movement in Sound

Answer 18

-molecules nearest the source are set in motion first
-molecules of air vibrating in SHM disturb molecules next to them and are transmitted away from source

Question 19

Longitudinal Wave

Answer 19

-particles move in same direction as wave movement
-sound waves
-pulling or pushing a spring (back and forth motion)

Question 20

Transverse Wave

Answer 20

-particles move up and down
-ropes at gym exercise movement
-molecules move at right angles to the wave
-tossing a stone in water

Question 21

Intensity

Answer 21

-correlate of amplitude
-loudness of a sound

Question 22

Prerequisites for Sound Production

Answer 22

-source of energy
-vibrating source
-medium of transmission
-a receiver

Question 23

What can interference cause

Answer 23

-sound waves to cancel out: complete opposites, destructive
-sound waves added together: amplify signal, constructive

Question 24

What is interference caused by?

Answer 24

-two or more sources of sound at one time
-reverberation

Question 25

Reverberation of Sound Waves

Answer 25

-sound will persist too long and affect perception -sound may be louder in some places and quieter in others

Question 26

Fundamental Frequency

Answer 26

-1st harmonic -frequency that sticks out most in perception -lowest freq out of all hramonics =most audible

Question 27

Periodic Sound Waves

Answer 27

-pattern of vibration; however complex, repeats itself the same way -vowels and voicing

Question 28

Aperiodic Sound Waves

Answer 28

-vibration is random and displays no repeatable pattern -constriction

Question 29

Harmonics and Overtones

Answer 29

-1st harmonic: fundamental -2nd harmonic and 1st overtone -3rd harmonic and 2nd overtone -4th harmonic and 3rd overtone -5th harmonic and 4th overtone -6th harmonic and 5th overtone

Question 30

Harmonics and Amplitude

Answer 30

-harmonics in a series tend to decrease in amplitude/intensity as freq increases

Question 31

As the tine of a vibrating tuning fork moves away from its rest position, the force of ______________ increases.

Answer 31

Elasticity

Question 32

The times of a tuning fork vibrate in ________ _______ motion

Answer 32

Simple Harmonic

Question 33

In an area of ___________, air molecules are close together.

Answer 33

Compression

Question 34

The number of frequency components in a simple wave (pure tone) is ______.

Answer 34

1

Question 35

True or False: The amount of force applied to a vibrating body determines the frequency of vibration.

Answer 35

False

Question 36

Waves with more than one frequency component are ____________ waves.

Answer 36

Complex

Question 37

If the 5th harmonic of a complex periodic wave has a frequency of 600 Hz, the fundamental frequency of the wave is _____ Hz.

Answer 37

120

Question 38

If the fundamental frequency of a complex periodic wave is 250 Hz, the frequency of the 7th harmonic of the wave will be _____ Hz.

Answer 38

1750`

Question 39

__________ is the term used to describe the decrease in the amplitude of vibration over time.

Answer 39

Damping

Question 40

In a complex periodic wave, each frequency component is a whole-number multiple of the _________ _________ of the wave.

Answer 40

Fundamental Frequency

Question 41

The frequency of a periodic wave with a period of vibration of 0.002 m/s is _______ Hz.

Answer 41

500 Hz

Question 42

The period of vibration of a sound source with a fundamental frequency of 2000 Hz is ______ m/s.

Answer 42

.0005m/s

Question 43

The perceptual correlate of frequency is ________.

Answer 43

Pitch

Question 44

The physical correlate of loudness is __________ of vibration

Answer 44

Amplitude

Question 45

True or False: Lower frequency sounds have longer wavelengths than high frequency sounds.

Answer 45

True

Question 46

Units of equal loudness are called ________.

Answer 46

Phons

Question 47

True or False: Resonance is the result of forced vibrations.

Answer 47

True

Question 48

True or False: The vocal tract is modeled as a half-wave resonator.

Answer 48

False

Question 49

The frequency components of complex periodic waves are called _________.

Answer 49

Harmonics

Question 50

Pitch is scaled in units called ______.

Answer 50

Mels