Cockpit Noise

[jkb458]

Quote: flight2000

[Magnum]

Quote: alex

I replaced the Bose x with a set of a20's and the difference is quite noticeable. On takeoff with the x's the anr appeared to fail especially during the roll. The a20's reduce the noise level considerably more and during takeoff they don't skip a beat

[triple8s]

I thought about the Halo's before I went Bose but thought it might make me itch.

[triple8s]

I thought about the Halo's before I went Bose but thought it might make me itch.

[rob]

I have a set of JH Audio in-ears and a set of Halo's. the JH Audio's cost 3x as much (not including the ear molds) and are only slightly, if at all, better. They are a bit more comfortable for me, but I'd gladly wear either over any traditional headset.

 

[M20E-1964]

Anyone know how the David Clark - headsets inc conversion compares to the Bose X.

 

Found a used Bose x for $500.00.   Comsidering it. 

[MooneyMitch]

My opinion based on actual usage of both headsets, and my perception, the Bose X is a bit quieter and does not apply quite as much pressure.  I don't personally find the DC a problem for pressure at all.  Maybe I'm just not that critical of that situation. 

Most of our flights are 2 hours or less.  With that said, we have used the DC's during our flight to Kerrville, TX last year, and to Oshkosh in 2008.  No David Clamp issues for me, but my co-pilot may chime in about this subject!

The DC/Headsets Inc. does a great job attenuating.  I am confortable using either the Bose X or the DC modified.

gmcd.  Please email me if you would.  sanluisjazzband@charter.net  Mitch

[KSMooniac]

Quote: gmcd

Anyone know how the David Clark - headsets inc conversion compares to the Bose X.

 

Found a used Bose x for $500.00.   Comsidering it. 

[nels]

I am sort of new to the Mooney forum but I will say that I am surprised no one has attempted reducing the noise in the cockpit. The lizard skin sounds like something cheap and simple. I would want to try it on something else first but it may be a good anecdote for the noise. A 16 oz can may only weigh 10 oz after the solvents are gone.

[DrBill]

I have the Lightspeed Zulu now and love them.  I started with the Sigtronics, then David Clark then Lightspeed XL ---> 3G and now Zulu.  Last Friday I flew for 1/2 hr with the David Clarks for a post annual check and what a difference.  Sat I flew almost 4 hrs with the Zulu.  Night and Day.

Best money I ever spent.

BILL

 

[M20E-1964]

Tonight I wore my instructors Bose X's for about an hour.... then flew with my DC's for an hour. The bose made a difference, but not as much as I thought it would. Kinda disapointed.

I noticed that when I put on my glasses, the seals on the Bose let in some noise (which is understandable). When when I put on the foggles, it was more noise let in.

I'm kinda on the fence now... Bose X for $ 500.00 used or the Telex Stratus 50's.

Decisions.....

[DaV8or]

Quote: nels

I am sort of new to the Mooney forum but I will say that I am surprised no one has attempted reducing the noise in the cockpit. The lizard skin sounds like something cheap and simple. I would want to try it on something else first but it may be a good anecdote for the noise. A 16 oz can may only weigh 10 oz after the solvents are gone.

[flight2000]

I wouldn't rule out the rule out the QT Halo's so fast, especially since they have a 45 day money back guarantee ($359 for a set).  Try them and see if they work for you.  If not, send them back and spend more money for the ANR's.

Never have to worry about sunglasses, foggles, hats, or smashing your headsets into the headliner in turbulence again... If I'm paying that kind of money for an ANR headset, I don't want to make compromises with the seals breaking because I'm wearing sunglasses or foggles.   Longest I've worn them at any time is 4.5 hours and then another 2 hours.  It got to the point that I couldn't wear my DC's for more than 45 minutes without my ears hurting.

http://www.quiettechnologies.com/

Just my $.01 for today...

Brian

No, I'm not affiliated with them, just a big fan of their headsets.

[flyby201]

I snagged a Bose X headset on ebay a couple of weeks ago for $310.00.  They work perfectly and are in great shape.  I have had a Bose X on the pilot's side since I bought my M20J (it came with it) and bought the second for the co-pilot side (both panel powered).  My Bose X in my Mooney is considerably quieter and more comfortable than my DC's in my friends C-210 or C-172.

[aviatoreb]

Quote: johnggreen

I have never flown any Mooney but my Bravo and a couple of Ovations; all of which had Bose.  In this day and age, flying without ANR's is like smoking unfiltered cigarettes, uh, dumb.

On another note, my Bravo is one of the quietest airplanes I have ever flown; takeoff, climb, and cruise.  At 15m, I wear the Bose but don't need them.  It's like being at home in my bed.  It is almost eerily quiet.  Far quieter than a Skylane or Bonanza.

You guys with older birds need to look into some good sound proofing.  Actually, it is not that big a job taking out and replacing the interior, but I'm not going there.  it would give you a far more enjoyable airplane.

I have a sound meter and may take some readings in my plane and post them just for the unbelievers.

 

Jgreen

[aviatoreb]

Quote: jkb458

[johnggreen]

To all.

Someone asked the specific question of converting Dave Clarks's to ANR.  That was my first step years ago.  I still have them and use them  in my Cub.  They work well but obviously not like a new $500 ANR.  BUT, I took mine to my avionics guy and let him do the conversion.  I can't remember what it cost, but I still saved money.

After that I bought a Stratus 50 and something else that I can't recall and everything works well.  Got the Bose witht the Bravo so now I have a pile of ANR headsets at my hangar.  I'll see what brand that other good set is, I just don't use them so I forget the name.

On insulation.  If you are going to the trouble of pulling interior, seriouly fellows,  DO IT RIGHT.  The labor is 90% of the job and your going to spray some snake oil on the interior of your airplane and think you'll solve a problem?

I have refurbished several airplanes over the years and the first step was ALWAYS interior insulation.  I redid a Beech 18 once and got the cabin so quiet that you could converse from the back seat to the front without shouting; the cockpit, well, that was a different matter.  Two P&W 985's spinning props 24" from your ears isn't easy to quiet.

On closing.  It is not just the sound the insulation will help with.  It is also vibration.  You don't realize what the physical pounding of vibration does to you on a four hour flight.  OK, that's enough.  To work to work.

Jgreen

[jelswick]

Very happy with the noise level in my 81 J using Lightspeed Zulus.  I prefer though to leave the ANR off myself until I get to cruise just to make sure I can hear if the engine is making any noises I wouldn't want to miss that might be covered by the ANR.  Once ANR is on, very pleasant noise level.

[Piloto]

Cockpit noise is a complex matter that comes from different sources in the cockpit environment. But they can all be addressed to make it more comfortably.

Engine noise and vibration being the major culprit. A 4 cylinder engine at 2400rpm would have a fundamental noise signature at 80Hz. So why instead of hearing a huming sound we hear a blasting noise. Well even thought the combustion explosions happens at 80Hz each explosion has a fast rise time creating a wide bandwidth of noise spectral that is the sound that we hear from the exhaust pipe. In a Mooney the best that can be done about this is to make sure the exhaust pipe opening is pointing downward and not to the side.

Engine vibration is actually at a low frequency (about 80Hz). The mass of the engine dampens the wide spectral noise of the combustion noise. To reduce the propagation of this vibration rubber engine mounts are used. Make sure your engine mounts and exhaust rubber mount are in good shape. Also any clamps holding hoses or cables into the engine should have a rubber liner. This keeps noise/vibration from propagating into the airframe.

Secondary vibrations are caused by the interior plastic side panels and glareshield. To demonstrate this tap with your car key on a side panel and then tap on a seat cushion. Notice the sound difference? The vibrating airframe is continously tapping on the side panels creating secondary vibrations at frequencies higher than 80Hz (rattling noise). You can pinpoint the culprit panels by pressing on them with your palm while listening to the change in noise. I found the glareshield to be the loudest one. Ideally all the interior panels should have been made out of rubber. This secondary vibration can be attenuated by placing rubber sheets at the point of contact between the panels and the airframe structure. I found this to make a substantial noise reduction greater than any insulation material. You can get the rubber material from an old inner tube.   

Air leaks is one of the most dominant noise sources and easiest to fix. They come from the cabin door, baggage door, pilot window door and vents.  You can tell where the doors is leaking by placing a rag along the door perimeter while listening for noise change. Because the Mooney doors have uneven gap clearance the typical rubber seal does not seal well after some time  For the doors I found foam weather strip (see attached photo) to work better and last longer than factory seals. You can get thenm at Home Depot for $4.79+tax.

Altitude helps a lot in reducing noise. Above 10,000 feet the air density is considerably less thus noise levels are lower. Also engine power is substantially reduced (non-turbo).

Number of passengers. Have you noticed that the more people you have onboard the quieter the plane is. This is due to noise absortion by the passengers bodies. The heavier the passenger the less noise. When making comparative cabin noise measurements it is important to keep the same body mass. 

Ear plugs are very effective and cheap. I found that using the rubber type (not foam) in combination with regular headsets provides better noise reduction than any ANR.  

Hope the above provide some help. I personally prefer keep hearing the engine.

Keep it quiet

José

 

[jetdriven]

Excellent, Jose.  Don't forget the prop pulse resonating off the windshield.

[Cris]

I've got a couple of DC ANR headsets that I've picked up over the years. They work great and DC is known for their customer service. The one thing I've done to them is add the Oregon Aero ear cushions and top pad. They are no longer "head clamps" and are still comfortable after long days (6+ hours) in the air.  

[Piloto]

Quote: jetdriven

Excellent, Jose.  Don't forget the prop pulse resonating off the windshield.

[ChrisH]

Great writeup, is there a shop that re-does interiors that is also known to take the excellent noise advise above into account? 

[rob]

The 201 windshield retro-kits discuss a noise reduction. Anyone who's made the swap care to comment?

[John Pleisse]

Quote: rob

The 201 windshield retro-kits discuss a noise reduction. Anyone who's made the swap care to comment?