I'm having trouble getting my internal microphone to be recognized in Arena 6. It works fine in version 5 on the same Macbook Pro (High Sierra v.10.13.3).
In version 5 (left in screenshot), I can select both Input 1 & Input 2 in the external Audio FFT Input dropdown box. I can use my microphone to make my videos react to the audio coming from it.
In version 6 (right in screenshot), I can only select Input 1 or input 2 seperately. Neither input gets recognised when I try to use External FFT as a reaction input for a clip.
All the other settings in that Preference/audio pannel seem the same.