Question for Bonehead helmet users

[Malndi]

We recently bought four Pilot-X helmets with CEP and after dialling them in we’re really happy, with one exception- background noise is dominating our intercom and transmitted audio to the extent that we’re virtually unreadable to each other and everyone else on the same frequency.

We all use different radios (A210, SL40, G430, GTR200) and we’ve each played with our mic gain and other settings. We’ve also swapped helmets and planes, all to no avail. We’re now trying to determine if/why the mics are the problem.

Our helmets came with Pilot PA-7X microphones. It’d sure help to hear from anyone else with a Pilot-X helmet about the type of mic fitted to their helmet and whether they have encountered a similar issue?

Thanks

[fl-mike]

I helped a buddy with another gee-wiz brand helmet, and I don't know why they use crappy mics in them (in my opinion). I threw on an old David Clark M-7A I had and it solved the problem (ANR feedback).

[Kahuna]

I have a bonehead I use in my Pitts. Never used in my RV (use a Gibson in my RV) and I only break squelch in certain maneuvers. Its a single hole so I dont care really. The Pitts is waaaaay louder in the cockpit than the RV. My bonehead has a mic foam muff. If I was bothered by it, I would try the leather mic muff before I did anything else. Available from many suppliers.

[jbDC9]

Originally Posted by fl-mike

I threw on an old David Clark M-7A I had and it solved the problem (ANR feedback).

This right here.

I fly some noisy stuff, so awhile back I tried that Pilot PA-7X “high noise” mic on one of my headsets. Meh, unimpressed. But, on my HGU-55 helmet I have the David Clark M-7A mic; works great even in the noisy AT-6 or stupid loud T-28D. Gotta have the mike muff to go with it though...

[Malndi]

Thanks for the suggestions.

I took the M7A mic from a spare DC headset and tried it in the helmet. There was a small improvement in sound quality, but my wingman said the background noise was still there, so I’ll try again with the addition of a leather mic muff.

But it’s interesting that the same M7A mic doesn’t suffer from background noise when used in the headset. I’m now wondering if the helmet is conducting noise and transferring it via the mic boom? I think this warrants more investigation.

[Gash]

I've been flying a Bonehead helmet in the Extra. Like Kahuna, I put that Oregon Aero mic cover on, but it still picks up a ton of background noise in my radio transmissions. Sometimes I have to hold my hand over the mic to reduce the noise. To answer your question, I really don't think it's being caused by conducted vibration. It's just good old 105 dB cockpit noise.

I just got sponsored by Lift Aviation and am getting one of their helmets to use in the Yak 50. This helmet will have the brand new Tiger Performance ANR headphones and mic (it's not advertised on Lift's website yet). I'm hoping for an improvement in transmission quality. I'll post a review here after I get a chance to put it through the wringer.

[MK77]

Very interesting. I used the super basic Bonehead helmet when I was conducting the phase 1 for my RV-7. Not sure what kind of mic capsule was in it. At that time I had no carpet, Vetterman 4-pipe exhaust and it was pretty loud in the cockpit (>100 dB-A SPL). Radio is a GTR200. Had no issues with breaking squelch on that mic as I recall.

Now I use a Sennheiser S1 and the mic performance is noticeably worse than others I used. A lot more background noise is picked up when I speak but it still doesn't generally break squelch unless I 'm speaking. A bit funny since I expected the Sennheiser to have better performance since they're known for their microphones.

I actually design microphones for a living. The type of mic, polar and frequency response will make a big difference in the amount of background noise it picks up. Most mic's for this application are what are referred to as "noise cancelling" which is a bit of a misnomer. More accurately they should be called "noise rejecting". Not sure what the specs of the mic in question are.

I'd be surprised if the mic 'muff' makes a big difference, at least not without impacting the quality of the speech pickup as well.

[rmarshall234]

This in an interesting thread.

I will soon be adapting a Bonehead Mamba skydiving helmet for use in the biplane I am building. The Mamba has a CF chin guard which I like, and I will mount the mic inside that chin guard recessed area. The ambient noise in this BP should be pretty high, it will be interesting to see if I incur the same noise issues as mentioned here. It might be several months before I'm up and running, but I'll report back if I have positive results.

[MK77]

Let me know when you are getting ready to mock up your helmet with the mic. I'm sure I can give you some pointers for maintaining the performance of the mic element with your mounting scheme.

[rmarshall234]

Awesome, will do, thanks so much!