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Audio Fidelity 0 / 16
Memory Rank Signal Static
1 [2 Marks]
Sound needs to be converted into binary.
(a) Define 'Sample Rate'. [1] (b) Define 'Bit Depth'. [1]
✅ Mark Scheme

(a) Sample Rate: Number of samples taken per second / Frequency of sampling (Hz).

(b) Bit Depth: Number of bits stored per sample.

Score yourself (Max 2):
2 [3 Marks Total]
A 10-second audio clip uses: Sample Rate = 3,000 Hz, Bit Depth = 8 bits.
(a) Calculate the file size in bits. Show working. [2]

(b) Convert your answer into bytes. [1]
✅ Mark Scheme

(a) Bits: 240,000 bits.

(Working: 3000 Hz * 8 bits * 10 seconds)

(b) Bytes: 30,000 bytes (240,000 / 8).

Score yourself (Max 3):
3 [3 Marks]
Describe how an analogue sound wave is converted into a digital file.
Use terms: 'amplitude', 'measure', 'binary'.
✅ Mark Scheme
  • The amplitude (height) of the wave is measured... (1)
  • ...at set/regular intervals (sampling). (1)
  • These measurements are converted into binary values. (1)
Score yourself (Max 3):
4 [4 Marks Total]
A musician increases the Bit Depth from 16-bit to 24-bit.
(a) Explain the effect on the quality. [2] (b) Explain the effect on the file size. [2]
✅ Mark Scheme

(a) Quality: More accurate to original sound / Better quality (1). Because dynamic range is increased (1).

(b) File Size: Increases (1). Because more bits are used per sample (1).

Score yourself (Max 4):
5 [4 Marks Total]
A producer needs to reduce file size (without using compression).
(a) State two changes to reduce size. [2] (b) Explain why one of these may negatively affect the listener. [2]
✅ Mark Scheme

(a) Changes (Any 2):

  • Reduce Sample Rate
  • Reduce Bit Depth
  • Reduce Duration

(b) Effect:

  • Sample Rate: Loss of high frequencies / less clear.
  • Bit Depth: Less dynamic range / more noise/distortion.
Score yourself (Max 4):