I have been on the bottom deck of a 90,000 ton ship = right at the front in an outside cabin 2nd cabin actually from the front of the ship. It was not Carnival - it was Norwegian Jewel a number of years back. Worse experience of my life and I am a very hardy cruiser. The waves were crashing against us at night when we sailed faster. The noise from the engines was terrible. I could not sleep. I had to go sleep upstairs on the 7th deck in the middle to avoid the thought that I was going to perish. Really it was that bad for me. It did not bother my mom nor my kids in their inside cabin across hall from me. On another ship Liberty this past March our friends had a inside cabin (we had balcony on deck 9) on Deck 4 in the middle and they were fine. DId not hear engines because they were in the middle. So I guess the morale of the story is if you want cheap, choose outside on deck 4 in the middle. You are away from the wave crashing and the engine noise at the front. Stay away from the front. My opinion.