Sample Rate
Definition
The number of audio samples captured per second, measured in Hertz (Hz).
Sample rate determines the frequency range that can be represented in a digital audio signal. By the Nyquist theorem, a sample rate can capture frequencies up to half its value — so 16kHz sampling captures frequencies up to 8kHz, which covers the fundamental frequencies and lower harmonics of human speech.
Speech recognition models typically work with 16kHz audio. Higher sample rates (44.1kHz, 48kHz) are used for music and high-fidelity audio but provide limited benefit for speech recognition and increase computational cost. Ummless automatically resamples audio to the rate expected by the speech recognition engine.