Thank you for your inputs.
I've taken about 20 longhaul flights in the past 2 years or so, of which 6 on A350XWB (all AY), 1 on B772ER (BA), 10 on B787 and a couple on B77W(JL/TK)/B77L(QR) and A330.
My quietness ranking is as follows:
4. B777 all variants
I really can't figure out how the B787 is louder to so many of you guys compared to the A350.
To me the difference is so big that I need to wear earplugs on the A350 while the B787 always baffles me by how quiet it is, no matter where I sit on it.
Granted, comparing the front cabins is a bit more complicated, but in economy class, the difference is more marked.
Someone above pointed out that AY has chosen cheap cabin furnishings, which could explain it, as I've ever only been on AY A350's.
I disagree that measuring decibels is the right process to compare aircraft cabin noise.
A microphone measures sound waves in a much wider frequency range than the audible range.
Also, our brains do not perceive all frequencies in the same way. High frequncy sound is much more of a nuisance at same decibel levels as low frequency sound.
Sure, there is also a difference between an aisle seat and a window seat. I've once been sat in a window seat on a B77W where the window panneling was driving me nuts but my neighbor couldn't even perceive it and a flight attendant who came to check on it, was looking at me from the aisle like I was making it up.
Does the B787 have active noise reduction?
The Boeing lists a lot of noise reduction features. http://www.boeing.com/commercial/787/by ... lmer-cabin
I'm not trying to advertise for Boeing, I'm not known to be a Boeing fan. But I think that they really did an awesome job on this matter.
For those who don't know, I have worked in maintenance on several aircraft types, including Airbus, Boeing and others.
You know, remove/install overhead bins, sidewall panels, ceiling panels. Engines, APU, etc...
So I'm pretty sure that I know why it happens and how to stop a panel from buzzing at me for 12 hours.
Usually the buzzing is caused by a poor fit of the panels, courtesy of poor manufacturing and poor design.
Some click into place, some need fastening but the holes rarely seem to align. Very often, those panels need to be forced into place and fastened while keeping force applied on them. The first time that I worked on overhead boxes (the ones for O2, video, air vents), I couldn't believe that all that was keeping them from sagging down was the rubber lining. A bit shameful for such expensive equipment.
I think that there is more to it on the B787.
Perhaps it's the lack of bleed air and the electric airco system? I once worked on finding a leak in the leading edge anti-ice system of an aircraft and you wouldn't believe how hard those joints and pipes were buzzing and screaming. We were running the air off the APU but it felt like we were cruising at altitude.
They did an awesome job on the panels, that I can confirm. I don't have the panel issues on the B787 that I have on most of the A350 or B777. It has never really bothered me on the A330.
The A350's hydraulic system is also very loud compared to the B787. On the B787 it's more like background noise, but on the A350 you are forced to hear it.
A 6 dB difference means that the B787's cabin noise is 4 times that of the A350. I really really doubt it.
I think that the only meaningful comparison is to record the sound on the same equipment at different locations in the aircraft and compare the recordings with our own ears.