Chapter 1 Exam Flashcards
1
Q
Frequency
A
The number of cycles per second (Hz)
2
Q
Natural Science
A
Study of physical world & phenomena
3
Q
Physics
A
Study of matter, energy, motion, force, physical processes and phenomena of particular systems.
4
Q
Acoustics
A
Study of production, control, transmission, reception, and affects of sound.
5
Q
Bioacoustics
A
Combination of biology & acoustics in study of sound production & reception in humans and animals.
6
Q
Psychoacoustics
A
The study of the relationship between physical characteristics of sounds and perceptual attributions.
7
Q
Mass
A
Amount of matter in object (g)
8
Q
Force
A
Influence causing object to change in speed/direction/shape. (N) (dynes)
9
Q
Weight
A
Force of gravity on object based on mass
(N)
10
Q
Volume
A
Quantity of space occupied by matter
11
Q
Velocity
A
Distance/Time
12
Q
Acceleration
A
Force/Mass
13
Q
Force**
A
Mass x Acceleration
14
Q
Pressure**
A
Force/Area
15
Q
Work**
A
Force x Distance
16
Q
Power**
A
Work/Time
17
Q
Intensity**
A
Power/Area
18
Q
What medium is human speech best perceived in?
A
Gas/Air
19
Q
Molecules of air are NOT stationary is the…
A
Brownian Motion
20
Q
The inverse relationship between air volume and pressure is…
A
Boyle’s Law
21
Q
Compression
A
Tine pushes air molecules to approach & collide, more molecules in a given volume causes air pressure to increase.
(High pressure & elasticity in air make molecules return to equilibrium)
22
Q
Rarefaction
A
Due to inertia & momentum, air molecules overshoot their equilibrium marks, which causes molecules to be more spread out, resulting in low pressure.
23
Q
Hooke’s Law
A
Restoring force is proportional to the distance of displacement & acts in opposite direction.
24
Q
Transverse Waves
A
Individual molecules move up and down at right angles to the direction that the wave is traveling, radiates in all directions.
(Water waves)
25
Longitudinal Waves
Individual molecules move parallel to the direction that the waves is traveling, radiates in all directions.
(Sound waves)
26
Simple Harmonic Motion (SHM)
When the pattern of a simple sound wave can be graphed out as a sinusoidal wave.
27
Waveforms
A graph with time on the horizontal axis and amplitude on the vertical axis. It changes in pressure that result from molecular motion.
28
Period
Time it takes for 1 cycle of vibration to occur. (t)
F=1/t
t=1/F
29
Wavelength
Distance travelled by 1 cycle of a sound wave.
30
Velocity
How fast a sound moves over a distance, depending on density & elastic properties of medium through which it is moving.
(Dense=faster, warmer=faster)
31
Average Velocity
331 m/s @ 0 Celsius
330/10=33 Hz
330/100=3.3 meters
32
Amplitude
Change of pressure due to molecular displacement overtime. (pascals)
33
Root-mean-squared (RMS)
Involves determining amp. of each point, squaring to eliminate all (-) values and then averaging. Lower than peak amp.
34
Periodic
A wave in which every cycle takes the same amount of time to occur as every other cycle, pure tone.
(May dampen over time)
35
Due to their thermal energy, air molecules are constantly moving in random patterns at high speeds, which is called what?
Brownian Motion
36
When sound occurs, air molecules are disturbed and set into movement, oscillating from _____ to _______.
Compression; Rarefaction
37
Boyle’s law states that, given temperature and mass remain constant, as volume decreases pressure will _______.
Increase
38
Are sound waves transverse or longitudinal waves?
Longitudinal
39
When displacement of air-molecules are graphed into a “waveform”, it reveals a ____ wave because amplitude of compression is equal to amplitude of rarefaction.
Sign Wave or Simple Harmonic Motion
40
When displacement of air-molecules are graphed into a “waveform”, it reveals a ____ wave because amplitude of compression is equal to amplitude of rarefaction.
Sign Wave or Simple Harmonic Motion
41
What two values do you need to determine wavelength?
Velocity and Frequency
42
A complex periodic wave consist of 2 or more frequencies that are mathematically related to each other. The lowest frequency of the series is the ________, and the remaining frequencies are called ________.
Fundamental; Harmonics
43
When two sound waves are in phase with each other, the resulting amplitude will increase due to _______.
Constructive interference
44
When two sound waves are out of phase with each other, the resulting amplitude will decrease/cancel out due to ________.
Destructive interference
45
Solve for Log10 (1,000)
3
46
Is the decibel scale a logarithmic scale or a linear scale?
Logarithmic
47
When using the decibel scale, a target sound is compared to a reference sound because it is a _______ scale.
Ratio
48
Does 5dB SPL= 5dB IL?
Yes!
49
A half-wave resonator is a tube that is open on _____ end(s), and only one half of the sound wave can fit in the resonator.
Both.
50
A quarter-wave resonator is a tube that is open on ______ end(s), and only one quarter of the sound wave can fit in the resonator.
One
51
Aperiodic
A wave in which individual cycles do not take the same amount of time to occur, no specific frequency/pitch.
52
Simple
Contains a single frequency, simple periodic wave is known as a pure tone, thin quality.
53
Complex
2 or more frequencies combine with each other, resulting in a complex vibration of air molecules, may be periodic (tonal) or aperiodic (noise).
54
Complex periodic sounds
Frequencies that are mathematically related to each other.
55
Lowest frequency is
Fundamental frequency (Fo)
56
Frequencies higher than fundamental are
Harmonics
57
Complex aperiodic are
NOT mathematically related
58
Harmonics can best be seen on a line spectrum, which is called…
Spectra
59
Line spectrum depicts what?
Harmonic content; sound quality
60
Transmission
Sound wave travels through objects
61
Absorption
Dampening of a wave when it comes into contact with materials that are soft/porous
62
Reflection
Sound bouncing back
63
Reflection
Sound bouncing back
64
Refraction
Sound changing direction because of air temp
65
Diffraction
Sound changing direction due to objects
66
Interference
Waves combining
67
Constructive interference
2 tones of the same frequency and phase relationship combine and act in the same direction, the resulting amp will be increased.
68
Destructive Interference
2 forces are identical frequency but 180 degrees out of phase, they cancel out
69
When frequency doubles….
It’s raised an octave
70
Pitch is…
How high or low we hear a sound
71
0 dB
Reference sound
72
Resonance
Tendency of a system to vibrate with highest amplitude in response to frequency that matches or comes close to natural frequency.
73
Natural Frequency
An object vibrates freely and is determined by the objects length, density, tension, and stiffness.
74
Resonant Frequency
The resonator undergoes the greatest vibratory response.
(Closer frequencies, higher amplitude of response)
75
Acoustics Resonance
Occurs when an air filled container or cavity is forced to vibrate by an applied frequency.
76
Tube Resonance
Based on build of tube; have harmonic frequency
77
Standing Wave
Producer when 2 identical waves traveling in opposite directions interfere
78
Standing Wave
Producer when 2 identical waves traveling in opposite directions interfere
79
Nodes
Points where waves interfere destructively and vibrate wi the minimal amplitude.
80
Antinodes
Points where waves interfere constructively resulting in max amplitude of vibration
81
Half Wave Resonator
Tube that is open on both ends, only one half of a wave fit in the resonator at any time
82
Half Wave Resonator
Tube that is open on both ends, only one half of a wave fit in the resonator at any time. (x2)
83
Quarter-Wave Resonator
Tube that is open on one end and closed on other, only one quarter of wave can fit in tube. (x4)
84
Cut Off Frequency
Point where intensity transmission is reduced by 1/2.
85
Bandwidth
Refers to the range of frequencies that a resonator will respond to a narrow range of frequencies and a wider range of frequencies.
86
Low Pass Filter
Responds to acoustic energy below a specific upper cutoff frequency.
87
High Pass filter
Passes energy above a designated lower cutoff frequency
88
Band Pass
Passes energy in a particular range of frequencies between low and high cutoff.
89
Band Stop Filter
Attenuates energy within the particular range of frequencies between low and high cutoff.
