If you have ONE by itself, it is not loud. If you have MANY, then it can be loud. Their "crow" sounds like a gargled cat-call (like the guys do when they see a pretty lady...
) and by itself is not bad. But you CAN hear them outside when they crow inside.
Mine are as annoying as all get out!! I have 2 A&M's that are about 5 weeks old that have recently discovered they are both males. One has a habit of crowing all night long!! With my bedroom door shut and the door shut to the room they are in, and with the TV on, I can still hear them!!
Mine were also obnoxious. I had five males and one hen in my livingroom, and the boys were all crazy. I got rid of two of the roos, got at least one hen for each roo (Tux wound up with two because I can't count), and two of the roos shut up immediately. My Italian then thought he was the king pimp of the hill and would crow about every 45 seconds all day, all night. I thought I'd somehow made a mistake and got another roo in with him, but no, it was definitely a hen.
He figured out she was a hen last week. I came home to find him staring down at an egg, looking at it as though wondering just how it got there. I could see him look between the hen and the egg and make the connection, and then he shut up during the night. Mornings are still quite exciting. When the light timer goes off, they all crow good morning.
It doesn't help that the button quail roo do their territorial peeping at random times - with four of them going off, it usually sets at least one of the Coturnix roos off.
They're much quieter than chickens or geese and I imagine that if they were outside, it would be tolerable. In the living room, not so much.