Changing Spartan voice

How do i change my Spartans voice?(Not the AI) It doesn’t seem to be an option in game or on the beta waypoint website.

For the record i’ve also tried downloading Halo Channel on my Android phone to see if i could do anything with that. As i expected, nope.
Though i heard there’s meant to be a beta you can opt into for it but i don’t seem to have that option…