Sound & Acoustics

Front 1

What is sound?

Back 1

A source that creates sound in a medium such as air.

Front 2

What is transduction?

Back 2

The conversion of sound/physical energy into electrical energy. The reverse also applies.

Front 3

Sound is a...(complete the statement)

Back 3

...psycho-physical perception in the auditory cortex of the brain.

Front 4

These two properties affect how sound travels through air:

Back 4

Air Density(Air Pressure) and Temperature

Front 5

Air possesses two properties that allow sympathetic vibrations to happen:

Back 5

Inertia and Elasticity

Front 6

Inertia is:

Back 6

The Movement of sound.

Front 7

Elasticity is:

Back 7

The Opposing Force.

Front 8

What is the Inverse Square Law?

Back 8

It is a guideline that describes how a sound's intensity, or loudness, diminishes based on distance travelled.

Front 9

The more dense the air is...

Back 9

...the slower sound moves through it.

Front 10

Inversely, the less dense the air is...

Back 10

...the faster sound will move through it.

Front 11

When the sound source and the waveform are moving through the medium parallel to each other, it is called...

Back 11

Longitudinal Wave Motion

Front 12

When the sound source and the waveform are moving perpendicular to each other, it is called...

Back 12

Transverse Wave Motion

Front 13

Amplitude, Period, Wavelength, Velocity and Frequency are all characteristics of what?

Back 13

Characteristics of a Waveform.

Front 14

Amplitude is measured in...

Back 14

...deciBels.

Front 15

What is the "dual nature of sound"?

Back 15

1). Sound is a physical disturbance.

2). Sound is a psycho-physical perception, or cognitive response.

Front 16

How do we calculate Wavelength?

Back 16

The Speed of Sound divided by Frequency.

eg: 1130 / 440 = 2.57 feet

Front 17

What does SPL stand for and what does it mean?

Back 17

SPL, Sound Pressure Level is a ratio of the absolute frequency, Sound Pressure and a reference level(usually the threshold of hearing[20Hz-20kHz]).

Front 18

When half the wavelength of a frequency equals the distance between two parallel walls; what is this known as?

Back 18

Standing Waves, or Room Resonance.

Front 19

The longest dimension of the room is at least half the wavelength you intend to hear for what?

Back 19

Bass frequencies.

Front 20

When sound bends around an object, what is it called?

Back 20

Diffraction

Front 21

What kind of curve reflects sound to a focal point?

Back 21

A concave curve.

Front 22

What is Flutter Echo?

Back 22

A series of rapid, repeated reflections caused by sound waves bouncing around between parallel surfaces.

Front 23

When two waves are at 180 degrees, what happens?

Back 23

Phase Cancellation

Front 24

How is phase described?

Back 24

In degrees.

Front 25

What is a Doppler Effect?

Back 25

When pitch is affected by a sound wave accelerating when moving towards you, and decelerating when moving away.

Front 26

Name the parts of the Outer Ear.

Back 26

1). Pinna

2). Auditory Canal

3). Tympanic Membrane

Front 27

Name the parts of the Middle Ear.

Back 27

1). Ossicles

2). Eustachian Tube

3). Air-Filled Chamber

Front 28

Name the parts of the Inner Ear.

Back 28

1). Cochlea

2). Tectoral Membrane

3). Organ of Corti

4). Basilar Membrane

Front 29

When the hairs in the Basilar Membrane are spread over Frequency dependant places, what is it called?

Back 29

Place Theory

Front 30

What is dBA?

Back 30

"Contour Filter A"; A High Pass Filter

A filter that approximates human hearing at quiet levels when testing equipment.

Front 31

What is dBC?

Back 31

"Contour Filter C"; Also a High Pass Filter.

Uses lower levels than dBA.

Front 32

What does Phon indicate?

Back 32

It indicates how loud a frequency must be in order to be as loud as 1kHz.

Front 33

What is Masking?

Back 33

When loud sounds drown out other sounds.

Front 34

What is Temporary Threshold Shift and how does it happen?

Back 34

It is the ear's way to protect itself from loud sounds. Muscles in the ear pull the Ossicles away to lessen vibrations to the Cochlea.

Front 35

What is Permanent Threshold Shift?

Back 35

Over exposure to loud sounds causing permanent hearing loss.

Front 36

When hairs go into shock they cause a permanent ringing in the ears. What is this called?

Back 36

Tinnitus

Front 37

What is Binaural Localization?

Back 37

The ability to locate where a sound is coming from.

Front 38

What is Inter-Aural Intensity Difference?

Back 38

When sound loses intensity over distance.

Front 39

What does the Pinnae do?

Back 39

They determine which direction a sound is coming from in our ear.

Front 40

What are the three elements in the Perception of Space?

Back 40

1). Direct Sound

2). Reflections

3). Reverberation

Front 41

Define Direct Sound.

Back 41

The purest form of sound. The shortest distance from the sound to the perceiver.

Front 42

What is Reverberation?

Back 42

Reflected energy from anywhere in a room. It tells us the material of the walls or surfaces it is coming from.

Front 43

What is Reflection and what does it tell us?

Back 43

Reflection is a single bounce from a surface to the perceiver. It tells us the size of a room and has the potential to colour the sound.

Front 44

What is Phon based upon?

Back 44

It is based on the equal loudness curves.

Front 45

What is a deciBel?

Back 45

A logarithmic scale relating loudness of sound to human hearing.

Front 46

What does the Organ of Corti do?

Back 46

Converts sound vibrations into electrical nerve impulses to the brain.

Front 47

Where is the Organ of Corti located?

Back 47

Inside the Cochlea.