Tutorial week 10

Question 1

what do you call a voltage, which varies over time

Answer 1

waveform

Question 2

The waveform of a pure tone is called a ___________

Answer 2

a sine wave

Question 3

How is a complex waveform related to simple sine waves?

Answer 3

a complex waveform can be broken down into simple sine waves or built up from them

Question 4

What is the frequency of a waveform with 4 msec between peaks?

Answer 4

250Hz

Question 5

You heard how a pure tone (of e.g. 500Hz) and a square wave or a sawtooth of the same frequency have a very different sound; the sine wave has a
“smooth” pure sound whereas the sawtooth has a much “rougher” sound.
That “quality” of the sound is called ________. But the pitch (related to the
fundamental frequency) of all three waveforms is the same.

Answer 5

timbre

Question 6

How 	large	a	difference	in	frequency	was	needed	for	you	to	detect	a	difference	
between	that	(variable	frequency)	test	tone	and	a	500Hz	tone?

Answer 6

under optimal conditions (not true here) good observers can detect the difference between 500 and 502 Hz

Question 7

Low-pass filtering a stimulus removes what frequencies…..?

Answer 7

Low pass filtering removes high frequencies

Question 8

And what does the sound sound like as you do so…….?

Answer 8

sounds become “muffled” or “blurry”

Question 9

Low-pass filtering of speech has the same effect. Which group of people
would experience such low-pass filtered speech….?

Answer 9

old people (such as you- you’re not exactly 13 anymore, are you?)

Question 10

what does Presbycusis mean

Answer 10

Presbycusis, from Greek presbys “elder” + akousis “hearing”, is age-related hearing loss.

Question 11

For frequencies above ______Hz, threshold gets worse very rapidly.

Answer 11

15000 Hz,

Question 12

Studies of _______ and other peoples living away from industrialised society suggests that they suffer less hearing loss

Answer 12

Easter Islanders

Question 13

what do you call the smallest bone in the body and where is it located?

Answer 13

stirrup, inner ear

Question 14

_____ are sensitive to frequencies much higher than humans are.

Answer 14

Dogs

Question 15

__________ is a change in air pressure. they are very small changes of a large
steady pressure

Answer 15

sounds

Question 16

A sound is a wave of __________ that moves away from the sound source slowly - with a speed of about 340 m/sec whereas light is a wave of
_________ with a speed about one million times greater than
sound: 300,000 km/sec.

Answer 16

1. mechanical disturbance

2. electromagnetic radiation

Question 17

Sound is change in air pressure and the measure of pressure is force per unit area. The units of force are ________ or _______. But since sound is a change in air pressure, to measure the amplitude of a sound it is necessary to
measure the extent of the change or variation. As you know from statistics, the ________ is a measure of variation and that is essentially how the
amplitude of sound is measured.

Answer 17

1. pascals (Pa)
2. micropascals (μPa)
3. standard deviation

Question 18

The threshold of human hearing for a 1000Hz tone is ____________.

human hearing range:

____ Hz to ___ Hz or ___Hz to ___ KHz

Answer 18

1. 20 micropascals (μPa)
2. 20 Hz to 20,000 Hz or
   20 Hz to 20 KHz