Solution 1:
Keynote uses the system sound input device, set in System Preferences → Sound → Input. Choose your preferred connected input device from this list, then start the recording in Keynote.
Keynote record slideshow with external mic
Solution 1:
Keynote uses the system sound input device, set in System Preferences → Sound → Input. Choose your preferred connected input device from this list, then start the recording in Keynote.