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Flashcards in Audition Part 1 Deck (29)
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1

what are the two steps of sound & what do they mean

compression = pushing air molecules together
rarefraction = then stretches them apart & repeat..

2

what is a pure tone?

a tone with one frequency

3

what is a wave of a pure tone called

sine wave

4

a graph of pressure changes over time is called a...

waveform

5

what are the three critical features or parameters of waves

-frequency: how many full waves in a second (in Hz), corresponds to pitch of the sound - pitch
-amplitude: how high is the wave? (deciBels, or dB), corresponds to loudness of the sound - loudness
-phase: how far through the wave are we (degrees) - timbre

6

what are sound waves?

linear e.g. they add together logically (sum the values at each point in time)

7

what are natural sounds a collection of?

simple sine waves added together

8

the waveform of any sound can be expressed as what?

a sum of sine waves with different freqs, amps & phases

9

what is fourier analysis

when you decompose a complex sound into its component frequencies, amplitude & phase

10

what happens when you add two soundwaves

the frequency stays the same but the amplitude gets higher

11

what happens when you add sounds of different frequencies

they form a complex wave

12

discuss a complex wave form

-made up of sounds of different frequencies
-wave forms are periodic (they repeat) the x-axis (time) gives little info

13

what is a spectrum

when you re-plot the wave-form graph as amplitude vs frequency rather than amplitude v time

14

what is a fundamental

the component with the lowest frequency

15

what does the fundamental frequency give

the pitch

16

what gives the characteristic sound in instruments that have the same frequency/pitch

the characteristic overtones

17

what are the three parts to the ear

-outer ear
-middle ear
-inner ear

18

what composes the outer ear

-pinna
-meatus

19

what composes the middle ear

-ossicles
-tympanic membrane (ear drum)

20

what composes the inner ear

-cochlea
-baslar membrane

21

what does the outer ear do

pinna: the flexible flap on outside of the ear
focuses sound waves into the ear canal (meatus)
shape and size of outer ear have the effect of amplifying medium sound frequencies

22

what does the middle ear do

the small bones (ossicles) in the middle ear transmit sound energy from the eardrum to the oval window in the ear

23

discuss the inner ear

containes a small coiled tube (cochlea) filled with fluid
-oval window & other window help to make the fluid vibrate
-has three parts
-transfers sound energy into chemical energy that is used by the nerves

24

how do the middle ear & the inner ear work together

the middle ear vibrates the inner ear's fluid & transmits this vibrating energy into the inner ear

25

what is the organ of Corti (inner hair cells)

receptor organ located in the cohlea has epithelial cells and allows for the transduction of auditorty signals into nerve impulses action potential

26

how many inner hairs do we have & where do they protrude from

3500, basilar membrane

27

how many nerve fibres do we have

50,000

28

the base of the baslar membrane is

thin & stiff & hears high frequency

29

the apex of the baslar membrane is

wide & floppy & hears low frequency