I have a Hahn's and he can be loud if there is some "scary" object in his sight, like a ladder. But he is not nearly as loud as a large macaw. For the most part he is pretty quiet. He doesn't make noise in the morning until he hears someone up and moving around. He will call out when we are in the kitchen because he wants to remind us that we have to share. But he is certainly not a noisy bird. That is just my experience with one bird.
P.S. If you want a small, quiet bird look at the African Senegal. They are delightful little guys!