Lecture 1-Basic Concepts

Question 1

Define Acoustics:

Answer 1

Underlying physical principles of sound propagation.

Question 2

Define psychoacoustics;

Answer 2

How humans perceive sound.

Question 3

Define sound:

Answer 3

Created by vibrations of air particles, when a sound source vibrates, it in turn vibrates the surrounding air, our ears are sensitive to this. the vibration is a FORCE (PRESSURE) acting on the air particles, measured in Pascal (Pa).

Question 4

Pressure fluctuates above and below atmospheric pressure, what is atmospheric pressure?

Answer 4

101kPa (kilopascal)

Question 5

Where do the particles get energy from?

Answer 5

The sound source transfers energy to air particles.

Question 6

In a waveform graph what does the 0 line represent?

What do the positive and negative peaks mean?

Answer 6

0 line represents regular atmospheric pressure.

Positive peaks mean higher sound pressure around the microphone/ear, negative peaks mean lower sound pressure.

Question 7

Define Amplitude:

Answer 7

The greater the sound pressure (or intensity), the louder the sound.

Question 8

Define frequency:

Answer 8

The greater the frequency, the higher the pitch.

Question 9

Define phase:

Answer 9

Sounds from different sources can add together to create louder sounds, or can completely cancel each other out.