Most macaws have the potential to be ear-splittingly loud, and most of them are naturally vocal. I had a mini macaw (Hahns macaw) when I was a kid and even though she was conure-sized, the volume she could produce was unbelievable.
In my opinion, parrots are one of the most intensive pets a person can own. For one thing, they live anywhere from 20-60+ years, depending on the species. Also, they require several hours of interaction daily, and are prone to behavioral problems (biting, screaming, plucking) if their emotional needs are not met. I'm a firm believer that, if you have a single doubt in your mind about getting a bird, you should listen to the doubt and not get one. There are unfortunately tens of thousands of birds out there that are currently looking for homes, because people wanted a cool-looking pet and had no idea of the care and time that's required.