SOUND

Sound: Oscillation of pressure transmitted through a solid, liquid or gas

How sound is represented and encoded

• 1. Sound is picked up by a recording  device  (e.g. microphone)
• 2. This moves a magnet  that is attached to a diaphragm  on the microphone
• 3. The sound is represented by voltage changes
• 4. This information is input  into an ADC
• 5. The ADC converts this into digital format
• 6. Users can save  the sound but compression is recommended

File size of sound = Bit rate * Length of sound in seconds

Bit rate = Sound resolution * Sample rate

Sample rate = 2 * frequency

• Higher sampling rate = bigger the file size
• Higher sampling resolution = more accurate sound, reduces the quantization error

• Can edit start and stop time
• Pitch alteration
• Filters - removing background noise 
• Fade in and fade out