Chapter 2

Question 1

What is sound?

Answer 1

• vibration
• auditory sensation
• organized movement of molecules

Question 2

Frequency

Answer 2

Number of complete cycles that occur in one second
1 Hz= 1 vibration/second
Pitch

Question 3

Phase

Answer 3

Start phase is at 0

Phase is always relative to the start point

Question 4

Amplitude

Answer 4

Measure of displacement

How far an object moves, peak to peak or baseline to peak

Question 5

Fourier’s theorem

Answer 5

Different shapes of time waveforms can be created by varying the relative amplitudes and phases of the summed sinusoids

Question 6

Force

Answer 6

Newton’s second law
= mass x acceleration
1 newton = 1 kg*m/s^2

Question 7

Work

Answer 7

When a force acts through a certain distance
F x d, unit is newton meter or Joule
The more force applied to an object, the more work is done

Question 8

Energy

Answer 8

The capacity for doing work, you must have energy to accomplish work
- 1 joule is 1N acting through a distance of 1meter

Question 9

Power

Answer 9

The rate at which work being done
The time within work is done
= energy/time
= joule/second
= watts

Energy converted to another form

Question 10

Pressure

Answer 10

Force/unit area
= pascals
1 Pa = 1N/m2
Larger pressure means a larger force being applied

Measure of sound amplitude

Question 11

Speed of sound

Answer 11

c= 345 m/s
Dependent on temp, density and humidity
Goes up when temp and humidity go up and when density goes dow

Question 12

Standard pressure reference

Answer 12

20 microPascals

Question 13

Sound pressure equation

Answer 13

dB = 20 log (p/p reference)

Question 14

Power/intensity equation

Answer 14

dB IL = 10log (I/I reference)

Units in watt/m2

Question 15

Intensity

Answer 15

Measure of sound power

Watt/m2

Question 16

Relationship between intensity and pressure

Answer 16

Power = amplitude2
Intensity = pressure2 
I = p2

Question 17

Standard power/intensity reference

Answer 17

10^-12 w/m2

Question 18

dB log scale

Answer 18

The closer you are to zero, the less pressure change you need to perceive the difference

Question 19

Period

Answer 19

Wavelength, one full cycle

1/f

Question 20

Friction

Answer 20

Does not alter frequency, only amplitude

Question 21

SAM tones amplitude line spectra

Answer 21

Fc (carrier frequency) 500Hz
Fc + Fm (mod freq) 560Hz
Fc - Fm 440Hz

*there is no energy at Fm

Question 22

Simple harmonic motion

Answer 22

When an object displaced from its equilibrium position is acted on by a force proportional to the displacement, the object will undergo a periodic motion (in the absence of friction)

Question 23

Instantaneous phase

Answer 23

Start phase both equal 0, but phase at different points in time differs between two waves (different frequency)

Question 24

Harmonic complex tone

Answer 24

All component frequencies are an integer multiple of the first one