Week 2: Waveforms

Question 1

Sound is propagated as a transient wave. True or False?

Answer 1

False.

Sound travels through air as a longitudinal wave; the pressure waveform is represented as a transverse wave.

Question 2

The speech of sound in air under normal conditions is approximately how many m/s?

Answer 2

330 m/s.

Sound travels approximately 3km in 1 second.

Question 3

All speech sounds are periodic signals. True or False?

Answer 3

False.

Speech consists of constantly changing mix of periodic and aperiodic acoustic signals.

Question 4

Conversational speech is approximately how much louder than the threshold of hearing?

Answer 4

50dBs

Question 5

Frequency and time are?

- Directly related
- Inversely related
- Opposite

Answer 5

Inversely related

Question 6

The vertical axis of an acoustic waveform represents?

- Frequency
- Pressure/Amplitude
- Intensity
- Period
- Cycles

Answer 6

Pressure/Amplitude

Question 7

Sound can travel through a vacuum. True or False? Explain.

Answer 7

False.

Sound requires a transmission medium to carry the pressure waveform.

Question 8

10. The duration of one complete cycle of an acoustic signal is defined as?
    
    • Velocity
    • Phase
    • Period
    • Complex
    • Aperiodic

Answer 8

Period T

Question 9

Transient sounds are aperiodic signals. True or False?

Answer 9

True.

Transient sounds do not have a repeating structure.

Question 10

Sound is carried directly from a source to the listener by moving air molecules. True or False?

Answer 10

False.
Air molecules are not displaced large distances by sound transmission: the pressure wave moves through air, not the molecules themselves.