If you can get through the first year it seems like the hens quack a lot less.
My Year old Chocolate Runner only quacks briefly on occasion, but her quack is loud. Her blue daughter was loud and quacked very frequently, I had to find her a new home when she was eleven weeks old.
My year old Khaki Campbell is quiet most of the time, her rare quack is not as loud as the runner. The 15 week old KC quacks a bit more but not nearly as much as the 18 week old Welsh Harlequin, who will burst into a fairly loud quack whenever she sees me.
My year old WH doesn't quack much more than the year old KC, and has slightly less volume, but she makes another noise I have never heard from a duck fairly constantly. It's not quite as loud as a quack, and kind of sounds like a donkey braying. I keep wondering if anyone else has ever heard a duck do this? I should learn how to upload a video.