Microphone advice needed.


Telex 602T




Back in the “old days” before things got complicated, I was flying a Cessna 150 with a handheld mic hooked to the panel that I would grab. Of course nowadays everyone sports an uberkool Lightspeed or Bose with an impressive boom electret mic and the little sponge wind muff. That's fine. I have a regular aviation modern headset with boom mic as well.

Anyway, I want to sort of homebrew my own ANR aviation headset, but want to keep it simple. I don’t want to mess with a mic and all the separate cabling and boom that are needed. I plan to use a separate push to talk microphone that I’ll plug into the panel. What I need from some of the many experienced readers here is some advice on aircraft push to talk handheld microphones. No VOX capability needed, just PTT.

Back when I was active in ham radio, I used a collection of magnetic, dynamic, and electret microphones. Cessna ARC avionics, Narco, etc. are some of yesterday’s obsolete radios which are not often seen anymore. So, I am curious what hand held push to talk mics sound decent with today’s more modern Icom 200/210, Garmin, Trig, etc. radios? Recommendation on type of mic such as dynamic or electret. and manufacturer & model...Shure, Telex, Electrovoice, Turner, etc...?? would be appreciated.

What about picking up a decent electret mic element and and swapping out the guts of an old hand held carbon mic?

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Bagarre wrote: What about picking up a decent electret mic element and and swapping out the guts of an old hand held carbon mic?

Good idea. Older high end David Clark mic assemblies appear quite often on Ebay.

I was hoping to hear a suggestion of two for a currently available mic, or one that was really popular back in the day that I might try out. PTT mics are really cheap used since everyone uses a boom on their headset these days.

found this one on E bay, along with several other mics at various prices.

http://www.ebay.com/itm/TELEX-microphon ... Oh&vxp=mtr

If I remember correctly this one is a dynamic rather than a carbon and they usually sounded fairly decent.

I have the Telex in this ad: http://www.skygeek.com/60837-008.html?u ... aQodGsED2w

It works fine with my modern audio panel and radios, although I don't use it very much--it's a backup.

You might want to consider the Headsets Inc. ANR kit, to modify a current headset for ANR. They have kits for just about any headset, and from my several years of experience with mine, they have a great product.

Cary

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Cary wrote:
You might want to consider the Headsets Inc. ANR kit, to modify a current headset for ANR.

Thanks Cary for the tip on the Telex and the ANR. Here is what I want to do. I am really sort of fiddling around out of curiosity as to what can be achieved by home brewing a number of different noise reducing features into a headset. I want to modify a David Clark hearing protector headset, the model 19A. This headset is strictly for hearing protection and has no mike or ear cup speakers at all. It does feature an astounding 27dB of passive noise reduction and huge over the ear cup enclosures for lots of sound deadening material. It has impressive specs as shown below.


Noise Attenuation Data
NRR
27 dB Frequency (Hz) 125 250 500 1000 2000 3000 4000 6000 8000
Attenuation (dB) 17.6 25.0 30.9 33.9 36.9 38.4 39.0 37.7 35.7
Standard Deviation 1.9 3.0 2.2 1.3 1.5 2.1 2.1 2.5 2.2

I then want to add custom earbuds such as those from CEP
http://www.cep-usa.com/cep/civil-aviation


The shape of the earbuds can actually be even further customized to one’s individual ear anatomy.

So at this point I have a super Passive Nose reduction headset AND custom ear plugs. It may already be so quiet at this point that ANR would be of little further value. If not, I’ll throw an ANR circuit and transducer in there as well, although it may mean tossing out some of the noise reduction “stuffing” in the DC 19A.

I may also try to brew up a Bluetooth or NFC ( Near Field Communication) arrangement to make the headset entirely cordless starting first with the audio input

I am just doing this for fun and as an experiment. I do have regular headsets already.

Again, it begs the question…what about the mic. Well, yup, that’s where an old used PTT Telex might be the handy solution. Blue tooth a boom mic as well ?? .. I have thought about that too. That’s for another discussion. All experimental of course.

Anyway Cary and Dale Moul, thanks for the links, info, and the feed back ! This is one of those "fun" projects just to see what I can come up with.

Heck, you might come up with something much better than anything on the market. Then 10 years from now, when you're rich and famous, we can all say, "We knew him then!"

Cary

As you probably already know, most (all?) of the modern COM radios are designed for electret mics. The trick will be to find an electret NOISE CANCELLING handheld microphone. Shure and Astatic make the dynamic ones, but ....

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NunavutPA-12 said: As you probably already know, most (all?) of the modern COM radios are designed for electret mics. The trick will be to find an electret NOISE CANCELLING handheld microphone. Shure and Astatic make the dynamic ones, but ....

Exactly ! I hope to either find an electret modern handheld PTT or I will buy an old element. I notice a lot of old mics salvaged from David Clark H10-40 headsets seem to pop up un Ebay. That might be the ticket. Price around 30-40 dollars.


All this is just conceptual at the moment. It is what Einstein called a " Gedanken Experiment" .
People have compared me to Einstein before.... we are both about the same height.

Old carbon mikes were easy to "repair" - just had to bang em around a bit to loosen up the grains.
Could be done while still "flying the plane first"

Your experiments sound like fun. It's great to make useful equipment from old cast-offs.

One thing to keep in mind regarding noise cancelling mikes is that they have two sound ports. One is pointed more or less at the cabin, and one at the pilots lips. This allows the ambient noise to be subtracted from the speakers side of the mic. If you install a DC mic in an old case, I'm thinking you would need to open up a hole on the back of the old case.

I've thought about bluetoothing a headset. It would need the original headset, an amplifier to drive the headphones, and some sort of translator from headset mic to bluetooth input. Also, a battery pack to run it all. A lion battery is light enough. I don't think all that stuff would add enough to the headset weight to be objectionable, and getting rid of the wires would be great. I'm not so sure how you connect some bluetooth signal into your comm system, though. Do some comm/audio panels already have bluetooth?

tom

The latest in wireless technology-- just think a position report and zip... right out onto the airwaves it goes.
Crew intercom built in. ANR too. This does it all!

FWIW, there's a Telex "ice cream cone" mic for sale on the AOPA website right now, asking $100. It doesn't say whether it's a dynamic or electret, and that shape was made in both.

Cary