​Walt

• ​To understand how sound can be stored in digital form.

• To understand what factors can affect the size of a sound file and quality of feedback.

​Digital audio keywords

​Sample frequency/rate The number of audio samples captured every second

​Sample size / Bit depth Number of bits available to store each sample e.g. 16-bit

​Sample rate It is measured in Hertz (Hz)

​Bit depth/Sample size

​Bit depth is the number of bits available for each sample.

• The higher the bit depth, the higher the quality of the audio. Bit depth is usually 16 bits on a CD and 24 bits on a DVD.

  • Bit depth of 16 has a resolution of 65,536 possible values

  • Bit depth of 24 has over 16 million possible values.

• 16-bit resolution means each sample can be any binary value between 0000 0000 0000 0000 and 1111 1111 1111 1111.

• 24 bit means the maximum binary number is 1111 1111 1111 1111 1111 1111 which creates 16,777,215 possible values.

​Sample rate

​The sample rate is how many samples, or measurements, of the sound are taken each second.

• The more samples that are taken, the more detail about where the waves the higher the quality of the audio.

• Also, the shape of the sound wave is captured more accurately.

• Each sample represents the amplitude of the digital signal at a specific point in time.

• The amplitude is stored as either an integer or a floating point number and encoded as a binary number.

​Process of storing sound in binary.

• ​Audio file is inputted through a microphone and broken down into thousands of samples per second(Using ADC).​

• The more samples recorded per second the higher the quality of the audio file, but the more memory it will consume. Each sound sample is stored as binary data.

• The more bits per sample also increases the higher the quality of the audio, on a CD the bit depth is usually 16 bits.

• The more samples recorded per second the higher the quality of the audio file, but the more memory it will consume.

​Quiz

​Wilf:

​You understand the basic keywords of sound representation.

​

​Quiz

​Wilf:

​​ You understand how sound can be stored in digital form.

• You understand what factors can affect the size of a sound file and quality of feedback.

​Code: