First, there is a constant hum and vibration from the generators/engines that goes on 24/7. It is ever-present and if you like quiet, you will not find it aboard ship, not anywhere.
We have a silver suite, compact and pleasant at about 700 sq. ft including the bedroom, sitting area, bathroom and narrow deck that holds 2 lounge chairs and 2 small tables.
While the insulation between the suite and the hallways - and within the suite itself (meaning you don't hear noise from the bathroom if you are in the bedroom with the connecting doors shut) is quite good, still simply being on the ship is noisy.
Anything smaller than a silver suite would be claustrophobic - beware !