A high-fidelity digital master of a violin solo is recorded with a sampling rate of 96 kHz96\text{ kHz}96 kHz and a sample resolution of 24 bits24\text{ bits}24 bits. To prepare the track for a web broadcast, the audio is downsampled to a sampling rate of 48 kHz48\text{ kHz}48 kHz and a sample resolution of 16 bits16\text{ bits}16 bits.
Which option correctly describes the quantitative change in the uncompressed file size and the qualitative effect on the digital representation of the sound wave?
The file size is reduced to 13\frac{1}{3}31 of its original size. The maximum frequency that can be accurately represented is halved, and the quantisation error increases because there are fewer discrete amplitude levels.
The file size is reduced to 13\frac{1}{3}31 of its original size. The maximum frequency that can be accurately represented remains unchanged because both sampling rates exceed the human hearing threshold, but the quantisation error decreases.
The file size is reduced to 49\frac{4}{9}94 of its original size. The maximum frequency that can be accurately represented is halved, and the quantisation error decreases because there are fewer bits to introduce errors.
The file size is reduced to 12\frac{1}{2}21 of its original size. The maximum frequency that can be accurately represented is halved, but the dynamic range of the recording is improved.
36 exam-style questions on AQA GCSE Computer Science Representing sound. Each one has a worked solution and a mark scheme showing where the marks go.