Sample Rate
The number of audio samples recorded per second, measured in Hz or kHz. Higher sample rates capture higher frequencies. CD audio uses 44,100 Hz (44.1 kHz); professional recording uses 96,000 Hz (96 kHz).
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Sample rate (also called sampling frequency) measures how many times per second a digital audio system captures a snapshot of an analogue audio signal. The unit is Hertz (Hz), typically expressed in kilohertz (kHz).
Standard Sample Rates
| Sample Rate | Common Use |
|---|---|
| 8,000 Hz | Phone calls, voice (narrowband) |
| 22,050 Hz | Legacy multimedia |
| 44,100 Hz | CD audio, MP3, standard digital audio |
| 48,000 Hz | Professional audio, video production, DAWs |
| 96,000 Hz | High-resolution audio, professional recording |
| 192,000 Hz | Studio mastering, audiophile equipment |
The Nyquist Theorem
To faithfully capture a frequency, you must sample at twice that frequency (the Nyquist theorem). Human hearing reaches approximately 20,000 Hz, so 44,100 Hz captures all audible sound with headroom.
Higher sample rates capture frequencies above human hearing — useful for professional processing that benefits from headroom, but not perceptibly different during playback.
Common Confusion
Sample rate is NOT the same as bitrate:
- Sample rate: How many samples per second (44.1 kHz, 48 kHz)
- Bit depth: How many bits per sample (16-bit, 24-bit)
- Bitrate: Total data per second = sample rate × bit depth × channels (e.g., 1,411 kbps for 44.1 kHz 16-bit stereo WAV)