Can't hear you, speak louder !!!!!
When I was flying the /400, we were wearing headsets the whole time. I think it had more to do with where the loudspeaker are located ( I understand it's the same on the 777 ) than the aircraft being really noisy.
On the 320 we use the headset up to 10 000 ft and then are on loudspeaker and it's fine. Trust me, there nothing noisier than a first generation 320 !