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Term 1 Theory Prep > Sound Theory > Flashcards

Sound Theory Flashcards

1
Q

Hertz is named after who? Why?

A

Named after Heinrich HertzHe was the first person to conclusively prove the existence of electromagnetic waves

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2
Q

What is the generally accepted range of human hearing?

A

20 Hz - 20 kHz

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3
Q

What affects the speed at which sound travels?

A

Temperature and density of the given medium

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4
Q

When a sound is louder, how does it affect the frequencies?

A

As sound gets louder the frequency response becomes more linear—you perceive all frequencies more evenly rather than perceiving some frequencies as being louder than others

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5
Q

What is the threshold of pain?

A

approx. 120 dB

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6
Q

How loud is normal conversation?

A

Approx 60 dB

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7
Q

What is white noise?

A

All frequencies at the same actual volume

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8
Q

What is pink noise?

A

All frequencies as the same perceived volume

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9
Q

DEF: diffusion

A

The scattering of sound waves evenly throughout a given space

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10
Q

DEF: refraction

A

A change in direction of a sound wave caused by the sound wave hitting a medium through which the sound travels differently

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11
Q

DEF: absorption

A

When sound waves are absorbed into a medium and converted from sound energy into heat

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12
Q

DEF: diffraction

A

The bending of waves around an obstacle or spreading out of waves beyond small openings

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13
Q

How do high frequencies react when diffracted?

A

They are highly directional either focusing as they pass through an opening or being blocked by an obstacle

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14
Q

What is the speed of sound at 21° C?

A

343.6 m/s (344 m/s rounded up)

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15
Q

How does density of a medium affect the speed of sound?

A

The more dense the medium, the faster sound travels. sound travels fastest in solids, then liquids, and more slowly in gasses

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16
Q

How does temperature affect the speed of sound?

A

Sound travels faster in warmer temperatures and slower in cooler temperatures

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17
Q

How do you calculate the distance a sound is travelling?

A

d = c x t (Distance = speed x time)

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18
Q

How do you calculate the time a sound will take to travel at a certain distance ?

A

t = d/c (Time = distance / speed)

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19
Q

How do you calculate the speed at which a sound is travelling?

A

c = d/t (Speed = distance / time)

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20
Q

What is sound, technically?

A

Sound is fluctuation in air pressure that uses a medium to propagate, reaches our eardrum, vibrates our eardrums and registers as sound in our brain

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21
Q

What are the two types of waves in which sound can travel?

A

Longitudinal and transverse waves

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22
Q

What two periods make up a single cycle of a sound wave?

A

A period of compression (increased pressure), followed by a period of rarefaction (decrease pressure)

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23
Q

What is a zero crossing?

A

The centre line of zero amplitude in a sine wave that is reflected in DAWS

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24
Q

DEF: reflection

A

Sound bouncing off a surface and returning in the direction from which it arrived

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25
Q

How does sound behave when reflected off a concave object?

A

Sound becomes more focused/stronger

26
Q

How does sound behave when reflected off a convex surface?

A

It diffuses

27
Q

DEF: Envelope

A

The way a sound’s amplitude changes over time

28
Q

DEF: Attack

A

the beginning of the sound and the way it changes before it reaches its steady-state intensity

29
Q

DEF: Decay

A

the rate at which a sound fades to silence

30
Q

Formula for determining speed of sound at a given temperature?

A

c = 331 + 0.6 x t

31
Q

DEF: Sustain

A

the steady state of a sound at its maximum intensity

32
Q

What is the speed of sound at 0ºC?

A

331

33
Q

DEF: amplitude

A

The amount of pressure being exerted on molecules in dB

34
Q

what does RMS stand for?

A

Root Mean Squared

35
Q

DEF: root mean squared (RMS)

A

a calculation of the average of values over a period of time to determine the average perceived loudness

36
Q

What is the formula for calculating the length of a soundwave in meters?

A

λ = c / f

37
Q

How do you determine the added frequencies that occur as a result of the combination and interaction of two sine waves?

A

calculate the sum of both and the difference of both

38
Q

What is the formula for calculating phase shift in degrees?

A

Ø = Δt x 360 x f

measured in miliseconds

39
Q

What is the formula for calculating phase shift in cycles?

A

Ø = Δt x f

40
Q

What is the makeup of a triangle wave?

A

A sine wave plus odd harmonics, increasing in frequency and decreasing in amplitude stacked on top of each other

41
Q

What is the makeup of a square wave?

A

a sine wave with odd harmonics, but has more harmonics than the triangle wave

42
Q

What is the makeup of a sawtooth wave?

A

a sine wave with odd and even harmonics above the fundamental

43
Q

Comparatively, how do pink and white noise sound to us?

A

White noise sounds very bright because of the way our ears perceive sound.

Pink noise sounds darker because there is more low end content

44
Q

What does the fundamental tone determine?

A

pitch

45
Q

How does a triangle wave sound?

A

sounds brighter than the sine wave because it contains higher frequencies as part of the sound rather than just the fundamental

46
Q

How does a square wave sound?

A

brighter still than the triangle because it has more harmonics

47
Q

How does a sawtooth wave sound?

A

brightest of all the basic wave shapes because it has the most harmonics; more nasal

48
Q

Do sine waves start in or out of phase and by how much?

A

Sine waves start in phase

49
Q

Do cosine waves start in or out of phase and by how much?

A

Cosine waves start 90º out of phase

50
Q

DEF: masking

A

when a sound is covered up by another, louder/more harmonically rich sound in the same frequency range

51
Q

Why do sound waves travel faster in warmer temperatures?

A

The air molecules have more energy at a higher temperature and vibrate faster enabling sound waves to travel more quickly

52
Q

What is a longitudinal wave?

A

A wave in which the displacements of a medium are in the direction of or directly opposite to the direction of prolongation of the wave

53
Q

What is a transverse wave?

A

A wave where the displacements of a medium are at a right angle to the direction of propagation of a wave

54
Q

DEF: amplitude

A

With sound waves, amplitude is the extent to which air particles are displaced, which is experienced as the loudness of sound.

55
Q

DEF: frequency

A

Frequency is the speed of the vibration, and this determines the pitch of the sound. Measured by the number of wave cycles that occur in one second, measured in Hz

56
Q

DEF: phase

A

a single instant on a wave form

can also be an expression of relative displacement between two waveforms of the same frequency.

57
Q

DEF: wavelength

A

the distance between successive compressions or rarefactions as shown in the diagram below

58
Q

DEF: period

A

the time it takes to complete one cycle of the wave form. As the frequency decreases, the period of the wave form increases

59
Q

explain critical bands

A

the human ear can distinguish changes in frequency more easily at low frequencies than high frequencies. There are 24 critical bands in the human hearing range.

if two tones are in the same critical band they are not distinguishable as separate tones and instead the ear perceives the separate tones as modulating, beating, or masking.

60
Q

What is masking

A

when the perception of one sound is affected by the presence of another sound, effectively covering up the sound and making it harder to hear.

61
Q

how many critical bands exist in the human hearing range?

A

24

62
Q

What is the cocktail party effect?

A

The brains ability to focus on one particular sound or stimulus while filtering out a range of other stimuli, like how a party goes can focus on a single conversation in a noisy room

Term 1 Theory Prep (11 decks)

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