The A230 family's intermittent noises are nothing compared to the deep, loud drone of the 737-800. We've flown on both types over a dozen times each, so really do know the difference in sound between the two. A floor squeaking is nothing compared to the high-decibel drone that the 737-800 makes. People without sound sensitivity probably block a lot of it out because it's such a constant sound, but for those with extreme sensitivity it is a constant problem.
I've flown in an A380, which are supposed to be very quiet, but didn't find it quiet at all. Perhaps because we were flying very fast or there was a lot of wind? The average A320 is quieter than the A380 we flew on.
I have sound sensitivity as well and can't tune out the aircraft noises, every single one gets processed, and peak sound pressure on an A320 throughout most of the cabin is 3-5 db higher than in a 737NG. Also, while I can reduce overall SPL level very easily, earplugs can cut 25-30 db, noise cancelling headphones can get 15-20 on the Boeing and 5-10 on an Airbus, the A320's constant throughout the flight electro-hydraulic systems turning on and off can't be effectively filtered. Seriously, if you just have straight SPL sensitivity, get earplugs from a gun shop. They're cheap, 100% effective, and anything that reduces the bark of .30-06 to hearing safe also reduces an airliner's SPL to the level of a library.
As for your A380, as in all aircraft, the overall sound pressure in the cabin depends significantly on where in the aircraft you are. "Flying very fast," and, "A lot of wind" do not impact the noise - jet airliners all travel at roughly the same airspeeds in cruise, and they do not travel relative to the ground, but relative to the air, so wind has zero impact. Overall SPL on an A380 is lower than on an A320 by quite a bit, but it depends where you are in each aircraft. Especially once you get aft of the engines, the noise climbs significantly (this is what the Boeing engine chevrons aim to reduce).
By far the quietest narrowbody aircraft I've flown in are the MD-80's and 717's in the first class cabins, because the engines are all in the back - in the back of the aircraft though, you have to scream your drink order at the FA's.
Generally speaking, from my experience with over 20 segments in each of these airframes, the quietest location on Boeing 737's are the back of first class/front of coach - the cockpit window and nose shapes dating from the 1950's, that generates fairly significant wind noise, but you're still fairly far forward of the engines. The A320 family, A330, A340, MD-80, MD-90, 717, 757, 767, 777, and 787 all are quieter the more forward in the cabin you are. On the 747, the upper deck or forward of the 1L boarding door on the main deck are your best bets, and the A380 is forward part of the second cabin on the upper deck.
