for now i want to replace all astromech droids with HK models or some other "humanoid" ones

and this is more or less clear to me.
what's really buggin' me is that huge assasin droid makes those sweet "twit whits"

so is there a way to replace sound patterns or create a new one?
i'm not planning to do "voice over" for them, just add something like geth (@mass effect) sounds or something like that. click clacks and beeps
