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1. STORING SOUND

   • sound must be recorded by a microphone as an analogue signal
     • analogue signals needs to be converted into digital data so that computers can read and store sound files
   • An analogue to digital converter will sample a sound wave at regular time intervals.
     • The samples can then be converted to binary. They will be recorded to the nearest whole number.

2. SAMPLING

   • Sampling is the process whereby an analogue wave is converted into a digital signal. At specific intervals of time, measurements of the amplitude of the wave are taken and stored as a binary value.
   • SAMPLE RESOULUTION
     • he number of bits used to store each measurement of amplitude
     • a sample resolution of just 2 bits, would mean that only 4 different measurements of amplitude could be recorded, and the sound is likely to be very poor quality.
   • SAMPLE RATE
     • The number of samples taken each second
     • Measured in hertz
     • Higher sampling rate = larger file size
     • The frequency at which samples are taken

3. FILE SIZE

   • File size (bits) = sampling rate (Hertz) x resolution x time (seconds)
     • eg. 44100 x 24 x 180 = 190,512,000 bits = 23,814,000 bytes = 23.814 MB
   • The higher the sample rate, the larger the resulting file. As a result, sound files are often a compromise between quality and size of file.

4. BUT DEPTH/RATE

   • Bit depth refers to the number of bits used to record each sample.
     • Just as with images, the higher the bit depth, the more accurately a sound can be recorded, but the larger the file size. Typical bit depths are 16 bit and 24 bit.
   • Bit rate is a measure of how much data is processed for each second of sound.
     • Sample rate × bit depth = bit rate
     • As with sample rate, the higher the bit rate, the better quality of the recorded sound.