The 2 ships are from different era's. It's like comparing a Ford Cortina to a Ford Mondeo. I would be suprised if you could detect when the engines are even running as the propulsion system is completely different on the newer ships. Also the Royal Promenade on Voyager puts the whole cruise experience into a different dimension.
The Celebration is a much smaller older ship  compared with the voyager of the seas  using the newer deisel electric system with 3 pods so yes it should be much quieter and it has 14 decks compared to 10. There are further factors the location of your cabin inside/our etc but I doubt it would be as bad as you experienced but there is always some vibration on most ships caused by the sea conditions and the propulsion system.
Mr or mrs wilba, where in nuneaton are you from i lived there for 22 years.
Now if I told you that, everyone would know. (near G.E.Hosp.