what is sound

Question 1

what is sound?

Answer 1

• wavelength is the distance between one peak and the next
• sound is a variation of pressures of the air

Question 2

what is frequency?

Answer 2

• pressure goes up and down at a certain rate =the frequency
• frequency is the number of pressure cycles per second at point in space (Hz)

Question 3

sound waves vs light waves?

Answer 3

• both “waves”
• sound transmission from place to place can cause discernible delays
• the perception of different frequencies is much more significant for hearing
• for hearing, frequency is the take home message

Question 4

sound: speed, wavelength and frequencies?

Answer 4

• 340 m/s
• 1.7cm to 17m
• 20-20,000Hz (20Hz = 20 cycles per second)

Question 5

light: speed, wavelength and frequencies?

Answer 5

• 300,000,000 m/s
• 400-700nm
• THz

Question 6

how many dimensions do sound waves radiate in?

Answer 6

3

Question 7

frequency (Hz) vs pitch?

Answer 7

• tone can vary in frequency
• pitch is higher - is going up and down more frequency
• they are going up both in frequency and pitch

Question 8

what is amplitude?

Answer 8

• amplitude (how much variation in the pressure of the air overtime - Pa)

Question 9

what is intensity?

Answer 9

• intensity (pressure “variance” - just square the amplitude)

Question 10

what is the faintest sound you can hear?

Answer 10

the faintest sound you can hear at 1 kHz is a fluctuation of about 20 micro-Pascals

Question 11

why are there such differences between the hearing of different mammals?

Answer 11

differences that exist between the hearing of mammals is because of how big the mammal is

Question 12

what happens to sound as we go down in frequency?

Answer 12

go down in frequency - become gradually less sensitive to sound

Question 13

what does it mean that sound level is a log scale?

Answer 13

it makes the numbers smaller, compresses the range of numbers

Question 14

does loudness increase in proportion with either sound amplitude or intensity?

Answer 14

NO

Question 15

is the decibel scale a scale of loudness?

Answer 15

NO

Question 16

what is the magnitude estimation of loudness?

Answer 16

• give somebody a standard noise, say its worth 100 and give them a louder noise and ask them what number it is worth
• listener assigns numbers to the loudness of each sound (a broadband noise) which varies in level, compared to a reference sound with the value of “100”
• that is how people understood this is how we have a non-linear way of hearing things

Question 17

what are complex tones?

Answer 17

• the combined waveforms repeat themselves: they are “periodic”
• sounds simultaneously get added up - waveforms join each other
• form a more complicated looking waveform
• tones of 200Hz, 400Hz and 600Hz

Question 18

do frequencies that are in similar number ratios to each other, sound good?

Answer 18

YES

Question 19

what does the waveform of a bassoon look like?

Answer 19

• waveform repeats itself
• characteristic feature of harmonic sounds
• also called periodic sounds as they periodically repeat themselves