Glossary → Audio fundamentals
Audio fundamentals
Nyquist theorem
The Nyquist–Shannon theorem states that a digital system can perfectly capture frequencies up to half its sample rate — the 'Nyquist frequency'.
This is the mathematical reason 44.1 kHz suffices for 20 kHz hearing, and why capturing above Nyquist requires filtering: content beyond the limit does not disappear, it aliases into false frequencies.