When analyzing tracks, [Vocal] is grayed out and I can’t select it.

This might occur in the following cases.

Free Plan or Core Plan users

You'll need Creative Plan to use Vocal Position Detection and display.

For details on the features available in each plan, see here.

Your computer doesn't meet the system requirements for rekordbox

To use Vocal Position Detection, you'll need an AVX (Advanced Vector Extensions) compatible CPU.

Please check with your computer manufacturer to see if your computer's CPU supports AVX.

The system requirements for rekordbox is here.