Do silent freewheels exist?
Your hub has a normal freewheel, like described by Matt Adams (ratchet with pawls).

There are some models which have spring-loaded cylinders mounted around "tilted" teeth: when you spin it to one side, the cylinders slip. When you spin it to the other side, the cylinders are caught between opposite surfaces, and torque is transmitted by friction (there is no positive engagement between parts).

Lots of backpedal-brake rear-hubs have this system.

Shimano had a Deore LX named "Silent Clutch" with this mechanism, but it was heavy.



Also, I know at least one model (American Classic) which instead of the spring to load the pawls, have a rotary disc to engage and disengage the pawl, and a tiny hair-sized spring which act as the freewheel for this plate. It is a very silent and low-friction system: