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Leading Edge: Active Noise Reduction Upgrade

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December 2014-

Active Noise Reduction Upgrade
You can install ANR electronics into
an existing passive headset, and you
can do it by yourself.

Several months ago I explained the mechanics of human hearing and the physics of passive and Active Noise Reduction (ANR) headsets ("How it works: Noise Reduction Headsets," Leading Edge, March 2014).
The takeaway from that column was Passive+Active Noise Reduction (P+ANR) is superior to Passive Noise Reduction (PNR) only, but the average headset cost—$700 to $1,000—might be out of reach for many pilots.
But what if you could cut the cost down to around $200 by upgrading your existing PNR headset? Would that make the decision any easier?
With a kit from Active Headsets, Inc. (formerly Headsets Inc.), you can remove the original audio speakers from your headset and install ANR electronics. Installation of the new ANR electronics requires a bit of rewiring and some soldering to achieve the documented benefits of P+ANR technology—but at least you won't need to relegate your current PNR headset to a desk drawer.
If you want a guaranteed professional installation with an extended three-year warranty, or if you can't solder or don't have the extra time, for an additional $50 plus return shipping costs, Active Headsets, Inc. can handle the entire upgrade for you.
Will the result equal a $1,000 Bose aviation headset? No, but you may be surprised at how close the comparison is, particularly in very high-noise environments such as warbirds and experimental aircraft.
A top-of-the-line Bose is still much lighter than any PNR-only headset, and Bose uses proprietary techniques to outperform virtually all P+ANR headsets on the market. However, according to many "converts," an Active Headsets Inc. conversion handily outperforms purpose-built ANR headsets selling under $600.
As for audio quality, the system provides about a 2 dB boost to the audio volume level. The overall result is a substantial improvement in noise canceling performance and speech intelligibility. Conversion choices
As I stated earlier, for a $50 fee plus return shipping, Active Headsets, Inc. will handle the entire conversion for you. If you can stand being without your headset for the one- to two-week turnaround time, this is perhaps the easiest way to enter the P+ANR world on a budget.
Simply call the company, let Richard Trotter know you want to send your passive headset in for an ANR conversion, and he'll take it from there. (See Resources for contact information. –Ed.)
If you are an adventurist, the DIY approach can be faster and cheaper. And, if you get into trouble, a phone call to the company's technical support department will likely resolve things. If you don't wish to test your soldering skills, you can always enlist a friend with such skills. The installation is reported to be relatively quick and painless.

Three choices
Active Headsets, Inc. has three basic choices available for conversion of existing PNR headsets.
The M-001-A kit fits most all headsets with standard-sized ear cups, the most common being the David Clark H-10 series (H10-20, -30, -40, -50, -60, and -80).
The MX-001-A kits fit the David Clark H10-13 series headsets, which have slightly shallower ear cups and require the extra-clearance modules.
The M-002-A kits fit select models of Peltor headsets. (Note: If you own an H20-10 David Clark product, Active Headsets, Inc. requires a factory installation.)
Confused about which one will work for your headset? Give the company a call and they will make certain you purchase the correct kit.
The cost of the basic ANR kits start at $169 (for the M-001-A and MX-002-A) to $189 (for the Peltor ANR kit). Everything you need to do the conversion is included in the price; you will need to supply a few simple hand tools and the low-wattage soldering iron. Active Headsets, Inc. recommends using a multimeter so you can check the continuity of your connections, but it's not mandatory.
One of the things you have to do when converting your PNR headset is to run a wire between the battery pack and the headset to power the ANR circuitry. The kit provides a 60-inch cable for this purpose, along with cable ties to secure it to the existing main audio cable.
That will get the job done, but a cleaner solution is to purchase an all-in-one cable (P/N HA-009-K, the "AMP cable"). This cable costs $22 when purchased with the kit and replaces your existing main audio cable. It has the audio, microphone and power cable integrated into one cable. The result is a more straightforward installation.

The DIY process
The first step is in some ways the most difficult. There's just something about removing the old speakers from your faithful PNR headset that is so final. But creating omelets means some eggs have to be broken—so follow the instructions, remove the screws holding the old speakers to their housings and cut the wires as shown.
Keeping all the old parts is a good idea because if for any reason you are not satisfied with the ANR installation, your headset can be easily returned to its original PNR status.
From that point on, it's a matter of consulting the instruction manual, the graphical wiring diagrams and/or watching an online video. The conversion is logical in that you remove a cable or a part, install a new one, connect it as shown, and repeat the process for the next step.
If you elect to buy and install the all-in-one (AMP) cable, visit Active Headsets, Inc.'s website for a full-size color diagram (one for stereo headsets and one for monaural headsets) which clearly shows what wires go where.
I'd suggest you print the appropriate diagram using a color printer; then, as you replace wires and components, mark them off directly on the diagram. Be sure to double-check your work before you cross off the wire, part or cable.
If you follow the instructions, wire things up correctly and everything checks out per the instruction manual, it's time to head for your airplane, connect the cables to the appropriate mic, phone jacks and battery pack. Turn everything on and see what happens.
The installed ANR system will work independently (i.e., without plugging your headset into your audio panel) when power is applied, so you can test it at home without going to the airport. Of course, to test the audio and microphone, you must be plugged in to your aircraft's audio system.
If you elected to purchase the AMP cable and your luck follows mine, you will find that the audio may only function in one ear cup. Don't panic. On the new AMP cable you will see a very small recessed switch on the Y-block. (The Y-block is where the single main cable divides into three cables. —Ed.)
Move the switch to the other position (positions are marked "M" and "S") and most likely the trouble will go away. It's Murphy's Law in action: if there are two choices, the default choice will be the incorrect one for your situation.

The results
Between 125 Hz and 8,000 Hz, my David Clark headset's specifications call for 14.7 dB to 36.1 dB of passive noise attenuation. The Active Headsets, Inc. ANR conversion adds an additional 18 dB to 21 dB active noise attenuation across the spectrum where engine and prop noise occurs, primarily between 80 Hz and 500 Hz. Once you experience the reduction in low frequency noise levels, you'll wonder how you got along without it.
The ANR system also boosts the audio output level (volume) of the headset by about 2 dB. Technically, a 3 dB increase is a 100 percent increase in audio volume; however, it takes about a 5 dB increase for the ear to sense a doubling of the sound level. The effect I experienced was a "brightening" of the sound from the intercom and radios as opposed to making them seem nearly twice as loud.
Compared to a Bose aviation headset, the Active Headsets, Inc. conversion of my David Clark PNR product doesn't have the same hi-fi sound. It isn't as comfortable either, but customers have reported the "clamping sensation" of most PNR headsets seems to be reduced. (Apparently, part of the clamping sensation many pilots complain of is actually driven by the low frequency noise, and that is what ANR cancels out.)
The kit cost just $191, and the difference between the PNR-only David Clark and my new ANR enhanced version is amazing to me. Overall I'm very pleased with the results.

John Loughmiller is a 4,700-hour commercial pilot and CFII MEI-A. He lives in Kentucky with Donna, his wife of 40 years, and often commits random acts of aviation. Send questions or comments to This email address is being protected from spambots. You need JavaScript enabled to view it..


Active Headsets, Inc.
(800) 876-3374

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