Volume, Loudness and Noise

Volume measured in decibels/dB
1. Measured by a Sound Intensity Meter
  1. Volume relates to the amount of energy there is in a sound wave
2. The dB scale does not increase like normal numbers; an increase of 10dB means that the volume is 10 times louder, e.g. 90dB is ten times louder than 80dB
  1. An increase of 3dB means the volume has doubled
  2. This system is called the logarithmic scale
  3. 130dB is ten trillion times louder than 0dB
3. 0dB is the quietest most poeple can hear
  1. The Threshold of Hearing
4. 130dB is so loud it's painful
Noise is any unwanted sound
Some materials absorb sound
1. These are called Sound insulators
2. Can be used...
  1. To protect hearing
    1. e.g. ear defenders
  2. In buildings
  3. In cars
The brain adjusts to the change in volume to make it sound normal again
The intensity of a sound gets small as you get further away from the source
Loudness refers to how loud the sound seems to be to us.
1. This is often called 'perceived loudness'
2. Loudness is affected by frequency and volume is not.
3. Units to measure loudness include Sones and Phons

Resource summary

	Created by Sophie Plowright almost 11 years ago