If you come across one or more patches in Epic Choir whose microphone signals appear locked or greyed out, it may be due to samples not loading fully for this patch:
This is remedied by clicking on the Refresh button in the top menu bar of the plugin:
Clicking on this will refresh the patch and reload the missing samples, enabling the microphone signals once again for use:
If you continue to have issues, however, please do contact the Spitfire Audio support team using the Help widget below.