Representing Sound

• Sound is represented in digital form through sampling and storing it as a series of numbers
• Sound wave is converted into a digital signal through Analog-to-Digital Conversion (ADC)
• Digital signal represents the sound wave in binary form, such as 100100100100101001010011001
• Quality of a digitally converted sound wave is affected by:

  • Bit Depth: Represents the number of gradations of amplitude that can be represented in a digital waveform
  • Sample Rate: Determines how often the amplitude of a sound wave is recorded
• Sample Rate:

  • Frequency at which the amplitude of a sound wave is recorded, measured in hertz (Hz)
  • Higher sample rates result in smoother playback
• Bit Depth:

  • Represents the number of different gradations of amplitude that can be represented in a digital waveform
  • Measured in bits, e.g., a typical CD uses 16-bits which can store 65,536 amplitudes
• Size of sound sample:

  • Calculated as (Number of samples per second) x (Number of bits per sample) x (Length of sample in seconds)
  • For example, a sample size of 6 x 3 x 4 = 72 bits or 9 bytes
• Sound file size:

  • Total number of bits in a sound file, calculated as (Number of samples per second) x (Number of bits per sample) x (Length of sample in seconds)
  • Bit depth and sample rate affect the quality and size of the sound file