Default Ok Google everywhere

This one has me stumped. I can't enable OK google hotword on my M8, I've tried the following:

Cleared play services and search. Both are up to date.
Recently flashed arhd 9.1 and full wiped (Normal kernel)
Disabled xposed modules
Tried OK google everywhere in the search bar
My Nexus 7 and 10 have it so it isn't my Google account.

Any suggestions? Thanks.