I'd absolutely agree with this. I took an AC A330 to YYZ and a BA 777 back the next day last year and the difference in engine noise is very, very noticeable. The Airbus 330/340 series are so much quieter than the 777 and this is true whether the 777 is RR, GE or PW powered - I've been on all three types now.

In fact Airbus used to have an ad campaign on the low noise level in the cabin (was on a board at LHR near the garage in the T1-3 area for a while) where on a 340 a pax at the back says "stop snoring" and a pax in J up front replies, "sorry".