Sound Representation - Digital Audio
Part of Images & Sound — GCSE Computer Science
This key facts covers Sound Representation - Digital Audio within Images & Sound for GCSE Computer Science. Revise Images & Sound in Memory & Storage for GCSE Computer Science with 18 exam-style questions and 16 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 7 of 11 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 7 of 11
Practice
18 questions
Recall
16 flashcards
Sound Representation - Digital Audio
How Digital Sound Works:
- Analog sound: Continuous wave (air pressure changes)
- Sampling: Measure amplitude (loudness) at regular intervals
- Digital sound: Series of numbers representing amplitude snapshots
- Playback: Convert numbers back to sound waves through speakers
Key Sound Properties:
1. Sample Rate (Samples per Second / Hz):
- 8,000 Hz: Telephone quality (low)
- 22,050 Hz: AM radio quality
- 44,100 Hz (44.1 kHz): CD quality (standard)
- 48,000 Hz: DVD/video standard
- 96,000 Hz or 192,000 Hz: Studio/hi-res audio
- Higher sample rate: Captures more detail, better quality
2. Bit Depth (Bits per Sample):
- 8-bit: 256 loudness levels (low quality, hissy)
- 16-bit: 65,536 levels (CD quality)
- 24-bit: 16.7 million levels (studio quality)
- 32-bit: Professional recording
- Higher bit depth: More dynamic range, quieter background noise
3. Channels (Mono vs Stereo):
- Mono: 1 channel (single audio stream)
- Stereo: 2 channels (left and right, surround effect)
- Surround: 5.1, 7.1 (multiple speakers)
4. Duration (Length in Seconds):
- Longer duration = more samples = larger file