Sound Theory

Question 1

Speed of sound in m/s

Answer 1

343 m/s

Question 2

Speed of sound in miles

Answer 2

0.21313 miles approx 1/4 mile a second.

There are 1609.34 meters in a mile. 4.69 seconds for a to travel 1 mile.

Question 3

Two parts of a single sound wave

Answer 3

Compression and rarefaction (rare a faction).

Peak and trough.

Question 4

What is phase?

Answer 4

Describes the movement of a wave over time. The phase describes the point in the wave(voltage or air pressure) relative to the start of the wave cycle in degrees from 0° to 360°

Question 5

What happens when 2 identical waves are 180 degrees out of phase?

Answer 5

Destructive interference -

The compression of one cancels the rarefaction of another resulting in pressure equalisation. (no sound)

Question 6

What happens when 2 identical waves are 0 degrees in phase?

Answer 6

Constructive interference -
They effectively double up resulting in a wave with greater amplitude. The compression and rarefaction combine and provide more energy positively and negatively (voltage or air pressure).

Question 7

What is frequency?

Answer 7

The number of complete wave cycles (1 compression and 1 rarefaction) in 1 second (Hertz).

Question 8

What is the range of hearing?

Answer 8

20Hz - 20KHz

Question 9

Low range - Low-end frequency range?

Answer 9

20Hz - 200Hz

Question 10

Mid range frequencies?

Answer 10

200Hz - 5Khz

Question 11

High range frequencies?

Answer 11

5Khz - 20Khz

Question 12

What is amplitude?

Answer 12

The amount of energy in a sound. Our ears perceive amplitude as volume. Measured in decibels .

Question 13

What are decibels?

Answer 13

It’s a logarithmic unit for measuring volume. Two principal types of scaling of the decibel are happening. Amplitude and Power.