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Knowledge organisers / Data Storage: Sound

Calculate file sizes of sound

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Knowledge organiser

Data Storage: Sound

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What you need to know

Sound file size is calculated using the formula: sample rate x duration (seconds) x bit depth. The result is in bits and may need converting to bytes or larger units.

Key points

  • Sound file size = sample rate x duration (seconds) x bit depth.
  • Example: 44,000 Hz sample rate, 10 seconds, 16-bit depth = 44,000 x 10 x 16 = 7,040,000 bits = 880,000 bytes = 880 KB.
  • To convert bits to bytes: divide by 8.
  • Exam Tip:Always check the units in the question — the sample rate might be in kHz (e.g. 44 kHz = 44,000 Hz).
  • Common Mistake:Forgetting to convert kHz to Hz before calculating. 44.1 kHz = 44,100 Hz.