lec 2 and 3- ear and sound physics

Question 1

what is the difference between hearing and listening?

Answer 1

-hearing requires no effort
-listening requires effort and focus

Question 2

what are the parts of the ear?

Answer 2

-pinna: a part of the outer ear that is visible, funnels sound in
-external auditory canal/ear canal: sends sound down the ear
-tympanic membrane/ear drum: vibrates when sound strikes it
-malleus: first bone to send vibrations from ear drum to next
-incus: middle bone, sends vibration to next
-stapes: final bone that vibrates sound on oval window and into the liquid
-cochlea: receives vibrations and converts to signals
-semicircular canals: help with balance

Question 3

between what level does the pinna amplify sound?

Answer 3

1,000-3,000 Hz, most speech is in this range

Question 4

what frequency of sound enters first?

Answer 4

high frequency?

Question 5

what type of hair cells get worn out with age?

Answer 5

high frequency because they enter first

Question 6

what is the range of sound that the ears can process?

Answer 6

20Hz-20kHz

Question 7

is it harder for humans to hear low frequency than high?

Answer 7

yes

Question 8

is louder or quieter sound more flat?

Answer 8

louder

Question 9

what is sound?

Answer 9

the wavelike movement of molecules in a medium

Question 10

what are the type of properties sound has?

Answer 10

-physical (measurable)
-psychoacoustic (what we perceive)

Question 11

what is acoustics?

Answer 11

the study and analysis of sound properties

Question 12

what are the three aspects of acoustics? explain.

Answer 12

-production/generation: an object vibrates and mechanical energy is transferred into acoustic energy (e.g. speaker)
-propagation: sound travels from source to receptor through a medium (e.g. air)
-perception: the sound is received and interpreted (e.g. human ear)

Question 13

what type of waves are sound?

Answer 13

longitudinal waves

Question 14

what does sound travel the quickest in, in the middle, then slowest in?

Answer 14

solid, liquid, gas

Question 15

what Is the compression of the sound wave? what is the rarefaction?

Answer 15

-compression: compact particles
-rarefaction: particles are spreaded apart

Question 16

what does 180 out of phase do?

Answer 16

does noise cancelling

Question 17

what does 90 out of phase do?

Answer 17

is in between in replay

Question 18

what is Hz equal too?

Answer 18

cycles per second

Question 19

what is frequency?

Answer 19

rate at which a cycle of compression and rarefaction occurs, expressed in Hz (number of cycles per second)

Question 20

what is pitch?

Answer 20

-the ordering of frequencies on a related scale
-the higher the frequency, the higher the pitch

Question 21

what does going up one octave do to frequency?

Answer 21

it doubles it (e.g. from 20Hz to 40Hz)

Question 22

what is amplitude?

Answer 22

measurement of the deviation from normal atmospheric conditions and how much compression and rarefaction occurs, as measure of energy

Question 23

what is a decibel?

Answer 23

the relative intensity of a sound

Question 24

what is the normal decibel level for a conversation?

Answer 24

60 Hz

Question 25

what rule doubles the loudness of a sound?

Answer 25

-the rule of powers of 10
-10^1 will increase a sound by 10 decibels, making it sound twice as loud

Question 26

what is the envelope of sound?

Answer 26

the variation of intensity of a sound through time

Question 27

what are the parts of the envelope?

Answer 27

the attack, delay, sustain, and release

Question 28

what are some types of sound illusions?

Answer 28

-The McGurk effect
-phantom words
-spatial illusions (3d sound)
-shephard tone illusion