some freehubs click louder than others when freewheeling. is that the noise you are referring to? if so, if it annoys me, i disassemble the freehub and apply a bit of light blue grease i bought at Ace Hardware in a pint tub about 5 years ago. it quiets them down for a while anyway, maybe permanently.
IIRC freehubs and older freewheels traditionally had only two pawls that ratcheted on the teeth when freewheeling. now many have three, four, some even six pawls, god only knows why
. no surprise they are so loud, i guess.