Always take muffles wax ear plugs from Boots and if you do happen to get a noisey cabin or neighbours, the problem is hopefully solved.
Good idea, but I'd rather nip the problem in the bud and try to avoid noisey cabins. Most (all?) older ships have some!
We've had deck 6 forward of midships and no noise at all (apart from next door snoring!!!) there was vibration at the rear of the ship so if you think this will be a problem I would think that just going forward of midships would be OK. We love Celebration (have been on twice) and would return at the drop of a hat!!
The cabins that tend to be more noisy are those that are towards the rear of the ship. I sailed on the Celebration in 2007 and was on deck 7 - disabled cabin - and on the Spirit last year on deck 2 - midships, outside cabin - and both times I didn't hear any engine noise at all, just felt a bit of vibration from time to time but after a couple of days, you hardly notice this at all.