Frequently Asked Questions (FAQ's)
Question: 
What is noise?
  Answer: Noise is a sound, that is not desired to be heard.
 - 3340
Question: 
What audio frequencies can be heard by the human ear?
  Answer: The human ear can hear sound wave frequencies in the approximate range of 20 to 20,000 Hertz.
 - 166
Question: 
How fast does sound waves travel?
  Answer: At sea level, sound vibrations travel in the air at a speed of approximately 1087 ft. (331 m) per second.
 - 167



