Calculate file sizes of sound

1.2.4d Data Storage: Sound

Data Storage: Sound — Note 1 of 3

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.

What to know

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 technique

Tip:Always check the units in the question — the sample rate might be in kHz (e.g. 44 kHz = 44,000 Hz).
Mistake:Forgetting to convert kHz to Hz before calculating. 44.1 kHz = 44,100 Hz.

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