22.05kHz vs 44.1kHz — What's the Difference Between 'True Broadband' and Upsampling?

Upsampling 22.05kHz audio to 44.1kHz does not generate high-frequency content. Switching to an F0-conditioned 44k model results in approximately 7.4% energy in the >11kHz range, as measured in practice — we explain the decisive difference from mere resampling.