What is Sample Rate?
Sample rate is the number of audio samples captured per second, measured in Hertz (Hz) or kilohertz (kHz). It determines the highest frequency that can be accurately reproduced in digital audio—directly affecting audio fidelity and file size.
The Science Behind Sample Rates
Nyquist theorem: To accurately capture a frequency, you must sample at least twice that frequency.
| Sample Rate | Max Frequency | Common Use |
|---|---|---|
| 22.05 kHz | 11 kHz | Low-quality, small files |
| 44.1 kHz | 22 kHz | CD standard, most podcasts |
| 48 kHz | 24 kHz | Video/broadcast standard |
| 96 kHz | 48 kHz | Professional audio, overkill for podcasts |
Human hearing range: 20 Hz to 20,000 Hz (20 kHz)
Since humans can't hear above ~20 kHz, a 44.1 kHz sample rate captures all audible frequencies with room to spare.
Standard Sample Rates Explained
44.1 kHz (CD Quality)
- Origin: Designed for audio CDs
- Use: Default for music and podcasts
- Why it works: Captures full human hearing range
- Recommendation: Best choice for most podcasts
48 kHz (Broadcast Standard)
- Origin: Video production standard
- Use: Film, television, YouTube
- Why it exists: Syncs better with video frame rates
- For podcasts: Fine to use, no audible benefit over 44.1 kHz
Sample Rate and File Size
Higher sample rates = larger files, but the effect is smaller than bitrate changes:
| Sample Rate | Relative Size |
|---|---|
| 22.05 kHz | 50% smaller |
| 44.1 kHz | Baseline |
| 48 kHz | ~9% larger |
| 96 kHz | 2× larger |
Note: MP3 encoding masks much of this difference since compression dominates file size.
Why It Matters
For podcasting, sample rate is largely a "set it and forget it" decision. Unlike bitrate, there's little benefit to tweaking sample rates once you're at 44.1 kHz or 48 kHz.
Why 44.1 kHz is the standard:
- Full fidelity: Captures every frequency humans can hear
- Universal support: Every device and app handles it perfectly
- Efficient encoding: MP3 encoding optimized for 44.1 kHz
- Industry standard: Aligns with music production workflows
When sample rate actually matters:
| Scenario | Recommendation |
|---|---|
| Recording | 44.1 kHz or 48 kHz |
| Editing | Match your recording rate |
| Export | 44.1 kHz for podcasts |
| Video production | 48 kHz for sync with video |
Common mistakes:
- Recording at 96 kHz: Wastes storage, no audible benefit
- Mixing sample rates: Can cause audio sync issues
- Exporting at 22 kHz: Noticeably degrades quality
The practical advice: Record and export at 44.1 kHz. You'll never notice a difference from higher rates, and you avoid potential compatibility issues with 48 kHz in some older systems.