If its the freewheel noise that is loud, it's not that uncommon on Campag hubs.
You can make it quieter on more recent hubs (2015 and later) by adding some grease into the freewheel assembly. Easlier hubs, you can do the same thing but it's advisable to change the pawls and spring first (kit FH-BO014 if it's an alloy Campag or Shimano spline body, FH-BO014X1 if it's a steel Shimano-spline body) because earlier hubs had a weaker spring that used to allow the pawls to get gummed up with grease - its why the earlier hubs were lubricated with oil in this area, not grease.
Recent wheels get louder as the grease in that area of the hub slowly degrades and so a periodic clean-out and re-grease is not a bad idea if the noise bothers you. It's not doing anything any harm ...
That assumes that I've understood the issue correctly ...