I have been on 7 carnival ships and have NEVER heard noise from casino,clubs, or dining room. Occasionally if you are in the back on the lower floors on an older ship, you can hear engine noise, but thats it.
Steve is correct, I have never heard any noise from the casino. But if you are concerned, you can look at the deck plans and figure out which floor has the casino and don't choose a deck below or above it. You are more likely to hear music from the piano bar, disco or other entertainment areas then the casino in my opinion. The casino is only loud when I win money on the craps table...
Which ship? And, what type of cabin (inside/outside/balcony/suite)?
If you're asking about Carnival Victory (alluding to your other post asking for its age), we enjoyed Deck 2. We were in an outside cabin just forward of amidships, so it was a short walk to the atrium elevator.
As far as a quiet cabin, try to get one that is not adjoining to its neighbor. We had an adjoining cabin on Carnival Destiny and could hear a lot from the neighboring cabin. We did not have an adjoining cabin on Carnival Victory, and it was very quiet.
18 cruises on 5 different cruiselines and never had a problem with noise from anything except hearing engine noise every so often...you will sleep like a baby anyway.....not to worry....Have a Great Cruise...
For least noise just be sure the decks above and below you are also cabin decks, not activity decks. Also, generally the front of the ship will be quieter than the rear. One exception. If you're on a lower deck near the forward anchors, it can scare you right out of bed when they drop anchor.