what mic will work with late 2014 mini?
https://support.apple.com/kb/sp710?locale=en_US
it has line in so I would assume any 3.5mm minijack mic would work
also many usb webcams have build in mics which can work separately from the webcams image streaming
Personally, I am not a big fan of 3.5mm (either earphone or mic) due to few misfortune episodes in the family. They (mic/earphone) got broken and the end "plug" got stuck inside MacMini or iMac, from repetitive plug in&out and, of course, careless actions.
Rudegar is correct about webcams do have build-in mic, and I had no trouble with them.
Personally, my whole family has switched to USB earpone (with build-in mic) to keep my sanity in check.
microphone for mac mini
