:p You're looking for consensus in a forum of thousands ?[well maybe 100's active] Sheesh ...trying being on a quest of more than 2 players and finding a consensus...:p
when he talks you still won't know simple becuase the helmit is shaped differently therefore changing the ammount of muff and echo comming out of it.
And no, it would not muffle/change your voice enough to disguise or alter etc. Unless it was magically enhanced to do so.
Hmmmm I smell death, That must be Killy Mc Necro the guy from 227 Prantz!