Page 1 of 1

Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 12:16 am
by fanoftristars
So I know it's not high end measuring equipment, but I was playing around with the new Noise app on the Apple Watch while in the air. I think it does a pretty good job of capturing decibel levels. I'd love to put together a chart of decibel levels by aircraft by seat or at least gather some anecdotal evidence from those of us who fly. I was reading on Flyertalk that someone had measured on an MD-90 and found at cruise they were getting 84db on row 10 (first row of coach). My flight today on a CRJ-900 first generation was much quieter:
Row 1 81-82db
Row 4 77db
Row 9 (where i was sitting) 74db.

I didn't get a chance to make it to the back but guessing by the engines it's much louder. I mention 1st generation CRJ-900 because I hear the 'NextGen' is quieter.

I always thought the front of the plane was the quietest, but I guess it makes sense that the quietest part of the plane is probably 1/2 way between the front and the wings, curious if any of you have measured with your Apple Watch. I'm flying the A-321 CEO on Friday - I'll take some measurements then :)

Re: Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 2:08 am
by md11sdf
I wonder how many Db you would measure in the last row of seats of a DC-9-30 from decades ago?
Especially with that insane engine RPM oscillation...

Re: Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 2:19 am
by planecane
Is that A weighted or C weighted?

Re: Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 2:19 am
by patrickjp93
I can tell you you don't need measuring equipment to know the quietest seats of the A350 are directly over the wing box or otherwise the furthest forward. It's subtler with the 787 and other engine-under-wing craft, but the reasons why are fairly obvious:

1) distance from noise source is a direct, quadratic factor in determining how loud the noise source is.
2) air in front of a jet engine is under very low pressure compared to the exhaust
3) structural metal, as long as it isn't resonant with the noise source, is a great dampener.

And as an aside, who cares? It's all quieter than this little blast from the past :lol:

https://youtu.be/EI3owgIj6zs?t=243

Re: Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 3:00 am
by mandargb
I did that on Delta MD-88 (ATL-RDU) on last seat few months ago. came around 100db.

Re: Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 3:54 am
by fanoftristars
mandargb wrote:
I did that on Delta MD-88 (ATL-RDU) on last seat few months ago. came around 100db.

That doesn’t surprise me. I hear that DL flight attendants are authorized to wear ear plugs while in the jump seats at the back, but are asked to remove them for the service for “optics”

Re: Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 11:52 am
by lightsaber
fanoftristars wrote:
mandargb wrote:
I did that on Delta MD-88 (ATL-RDU) on last seat few months ago. came around 100db.

That doesn’t surprise me. I hear that DL flight attendants are authorized to wear ear plugs while in the jump seats at the back, but are asked to remove them for the service for “optics”

I just took OHSA noise training yesterday (with a team, I must keep the work environment within limits). 85dBa is the 8 hour limit. If 100db, those FA are close.

I know I avoid flying the MD-80 as when I buy coach, I've ended up in the back. It was just too loud to enjoy the flight and, of course, my Bose batteries died.

Lightsaber

Re: Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 12:22 pm
by MIflyer12
This points to why the observations 'Aircraft xxx is noisier than aircraft yyy' aren't worth much. It depends on where you're sitting, thrust levels, altitude and ambient noise (open gasper vents?) among other factors. Human memory of noise levels is poor, too, making comparison of xxx to yyy taken last month very difficult.

The FAA used to do aircraft noise footprints. Does it still? That doesn't necessarily relate to cabin noise, however.

Re: Decibel Levels on Aircraft at Different Seats

Posted: Thu Oct 10, 2019 1:45 pm
by exFWAOONW
The only noise footprints I recall were measured on the ground. Did they also measure inside aircraft?

Re: Decibel Levels on Aircraft at Different Seats

Posted: Sat Oct 12, 2019 8:11 pm
by FredrikHAD
I accidentally stubled upon this PDF from Fokker. In there you’ll find a noise map of the F50 cabin!

http://www.flyfokker.com/sites/default/ ... terior.pdf

I fly the ATR 72 a few times per year. My favourite seat is 2C (first row on left side, 2nd seat from the window) or 2D (also aisle seat) where you have plenty of legroom. I do like window seats but in the ATR 72, both the -500 and -600, the noise in 2A and 2E (window seats) is way higher than in the aisle seats in thet row. I once was late to the boarding and had to sit by the prop, but I was surprised that the sound level was so low in that seat. I was expecting a lot worse.

/Fredrik

Re: Decibel Levels on Aircraft at Different Seats

Posted: Mon Oct 14, 2019 6:10 pm
by fanoftristars
A couple more data points:
Sat in 11F on 737-900er. Was about 74db. Back of the cabin by the Lav was 81db

On a 737-800 today in 12D, constant 77db, in the back by the lavs 81-82db

Re: Decibel Levels on Aircraft at Different Seats

Posted: Mon Oct 14, 2019 6:25 pm
by DFW17L
I read the TU-144 Concordsky cabin was extremely noisy (90-95 db), due to the AC system. That sucker got hot at cruise speed and the Soviet aviation engineers weren't good at HVAC. Source: Moon, Howard. Soviet SST: The Technopolitics of the Tupolev-144. London: Orion Books, 1989. ISBN 0-517-56601-X, page 195.

Re: Decibel Levels on Aircraft at Different Seats

Posted: Mon Oct 14, 2019 8:10 pm
by rnav2dlrey
the upper deck of the A380 is easily the quietest cabin i've experienced.