One of the better applications of microprocessor technology in general aviation has been the ANR (active noise reduction) headset. But early ANR headsets were pricey and many still are. Enter Headsets Inc. and their conversion kits for many major brands of passive (non-ANR) headsets. AVweb's Contributing Editor Dave Higdon recently upgraded his David Clarks with the Headsets Inc. kit and found it to be an easy, worthwhile modification.
September 2, 2001
back, we waited far longer than wise to decide to equip our heads with active-noise-reduction headsets; even with a significant amount of sound insulation
installed in our classic Piper Comanche, the physical impact of segments lasting
three and four hours usually left us tired beyond necessity. Money actually
the shortage of it, as is usually our case blocked us from buying most of the
time. Even when we possessed the funds, the Comanche usually imposed other
priorities on our spending plans. And besides, we usually reasoned, our plane is
much quieter than most; people always told us so after a ride. So using oxygen
for the last hour of long trips usually proved good enough to perk us back up.
But thanks to a ride-along with a friend this past April, my partner and
bride, Annie, joined me at Sun 'n Fun with a newfound appreciation of the value
of ANR technology even as it left her astounded at the costs. She came to
Lakeland with our friend Jeff flying in his PropJet DLX Mirage, the turboprop
conversion of New Piper's pressurized single; Jeff uses first-generation Bose
ANR headsets. The flight down convinced Annie: We need to set aside the bucks
and buy ANR.
"Look," she told me, doing a little preaching to the choir,
"you fly a couple of hundred hours a year; that's a lot of noise exposure.
And anything that lets you hear ATC better and arrive fresher enhances safety.
I'm always a pushover for safety enhancements," she said, as she has many,
many other times.
So, we shopped until we damned near dropped, prowling buildings A through D
at Sun 'n Fun in a quest to find the best value in ANR headsets. We stopped at
every manufacturer's booth and sampled every design, usually trying on the
host's brand and then competing models graciously supplied by each host for the
purposes of objective comparisons.
Even though some of our comparisons seemed unavoidably subjective, we learned
along the way that price indeed influences quality. For example, one company's
new budget headsets under $300 and advertised honestly as having lower noise
reduction than its other models did in fact work less effectively than the
company's own $600 sets; throw in our discomfort wearing them, and even the low
price seemed inadequate to induce our interest. We didn't decide that the $1,000
Bose systems worked best we found them better in ANR and worse in audio
quality than Sennheiser's HMEC 300, which sell for about $600.
But we did find a strong middle ground in ANR headsets, priced between $300
and $500, where the noise reduction and audio quality sounded very good for the
money. We closed in on spending close to $700 on two headsets then we found an
alternative that, in our experience, matched even sets priced up to $600 each.
That alternative brand: Our own two-decades-old David
Clarks converted with kits from Headsets Inc. Yes, we sampled them, as well, in
the same afternoon-long marathon sampling session at Sun 'n Fun. Thankfully, the
Headsets Inc. booth also offered demos with several competing brands available
for comparisons including several of those brands and models we previously
sampled and liked.
The original speaker modules after removal
from the old David Clarks. Click image for larger version.
But between the show-special pricing and my satisfaction with the fit and
comfort of our Clarks, the idea of tackling a few hours of bench work clicked
with me instantly. Nothing like the prospect of saving about $400 to make me
anxious to haul out the soldering iron. The David Clarks originally came to us
with our first airplane, tossed in by a young man who planned to do little
flying in the future; if I screwed them up or if we didn't like them, selling
them for the cost of the Headsets Inc. kits would be relatively easy.
And then we'd buy new. Well, we've put more than 40 hours on our Headsets
Inc. David Clarks and my only regret is not making the change sooner. As you'll
read in a moment, the conversion process was relatively easy certainly no
challenge to anyone with even minor skills at soldering or reading instructions.
Better still, the ANR is effective, the audio clearer and the fit exactly like
the David Clarks fit before the conversion.
So, to give away the plot a bit early, this project is worth doing if you're
flying any brand of passive headsets that will take the kits. For about $190 and
a couple of hours of work per set, you can enjoy active noise reduction
comparable to several brands selling for two and three times the price. And you
can use the savings of $200 to $400 per head to enjoy a nice weekend flying trip
using your newly converted headsets and experience the reduction in fatigue
you'll feel upon arrival.
Is This A Conversion Or A Renewal?
From The Shells In, You Really Get New...
In essence, Headsets Inc. provides you with all-new hearing electronics
you can even replace the main jack cable which means that, upon completion
of the conversion, you essentially have all-new gear, with the exception of
the earshells, seals, headband, microphone and volume control of your existing
non-ANR headset. The kit includes new inserts to replace your existing
speakers. Those inserts carry an integral microphone and two speakers, one for
audio, the other for the ANR "white noise" that cancels background
sound. These integrated units, one for each earshell, also sport the
integrated circuit board and digital processor that "hears" the
background noise and generates the opposing-wave sound that cancels the
Front and back of the Headsets Inc.
speaker replacement modules. Click image for larger version.
To make the ANR modules work, the kit includes new foam sound insulation to
go inside the earshells, several pieces of wire, a new cross-over cable, a
length of resin-core solder, several small pieces of heat-shrink tubing to
cover and insulate the wire connections, a battery box, and a set of
instructions complete with color wiring diagrams. Finally, the standard kit
includes a power cable meant for securing to the headset cord.
My attitude toward securing an external power lead to our old headset
cables fell short of enthusiastic; our cables looked their ages and the jacks
themselves showed signs of wear and tarnishing. Besides, the single lead
already seems to tangle on every possible projection. So we opted for the
new-cable option the company offers. For an additional $20, we received
brand-new cords which consist of a new multi-conductor cable incorporating the
power cord and connector, plus new mic and headphone jacks.
Since we long ago installed new gel earseals, mic muffs and headpads,
completing the conversion basically overhauled our old units to zero time;
sure, the shells and metal headbands remain the same, but otherwise everything
in the hearing side of our headphones came away brand new. No, we didn't
replace our noise-canceling mics; no biggie. From what we hear, they work
great; in other words: ain't broke; ain't fixin' 'em.
...Test Twice, Snip Once; Test Twice, Solder Once...
As it worked out, installing the first Headsets Inc. ANR kit didn't really
require a volt/Ohm meter but it helped, going a long way toward confirming
connections before soldering wires and connectors together. In essence, I
needed only to follow the color-coded drawings and trust in my ability to
identify wires and terminals and connectors. You need to stay attentive during
disassembly every bit as much as you should when rewiring and installing the
ANR modules. Cut a wire at the wrong spot and you'll be back with that
multi-meter trying to troubleshoot a non-functioning headset.
Be sure of your selections, though, check twice and keep the process in
order and you should find nothing daunting about the job.
Removing the old components from the
original David Clark headsets. Click for larger image.
In essence, you first remove each cup from its mount, gently pull off the
earseals, remove the cloth covers tucked inside each cup, and remove each
speaker. Most of the work centers on two mounting screws that hold the
speakers firmly to the shell, and then disconnecting the wire leads from the
speakers. You'll pull out some old insulation and find a bundle of wires
behind each speaker, all of it color-coded. Following the instructions, you
disconnect the crossover cable and route the new one.
At this point, you've cut the internal wiring in several places and a
number of lose ends hang in front of you. No sweat; as long as you can trace
the wires or check them with a volt/Ohm meter, you can identify each one.
In our case, we also cut and removed the old main cable, which included
connections for the microphone; the new cable included its own instructions.
So, by paying attention to the loose ends and the extra diagram, restoring all
the right connections proved relatively simple. I merely traced the diagrams
that came with the new cable when appropriate and referred to the master diagram when it
First, the new crossover cable went into place, followed by the new master
cable. A hint is in order here: Put a little dish soap in a saucer and use
Q-Tips or cotton swabs to lubricate the inside of the earcup grommets and the
outer shell of the cables. Otherwise, these rubber-against-rubber passages
become difficult to make. A little bit of Dawn detergent allowed the cables' outer
shells to slip easily through the grommets.
The old speaker is removed, exposing the
David Clark's innards. About to cut the wiring. Click image for larger
Now, with the new cables in place, pair off the individual wires from the
cables to the corresponding pieces of wire still inside the earcups to the volume
control, for example and to the wires that will connect to the modules.
Here's when a multi-meter makes things easy. Set the meter to test resistance
and you can confirm each connection before proceeding to solder the
Once the internal wires, cross-over cable connections and power lines are
connected, it's time to connect the wires that link the modules to the
headset's harness. You face three small wires and three tiny holes in the
circuit boards, each one already surrounded with solder. One is a common
ground, one carries power for the processor; the third carries the airplane's audio
signal. Strip the wire ends about 3/16ths of an inch, slip them into the
proper hole the diagram covers it all and touch the iron's tip to the
wire. When the solder wicks onto the wire, you've made the connection.
Closing the headsets basically involves
tucking the wires behind the new insulation, test-fitting the modules, adjusting
the wires' placement, making a final check for proper fit, mounting the new
speaker modules in place and reassembling the
headsets into one complete unit. Sounds simple but, in reality, this step requires as
much patience as the cutting and soldering. You may need a couple of extra
tries to get the wires sorted and tucked away; a bit of tape or a bit of glue
can help here. But once you've got it arranged, it gets easy.
The modules don't actually go inside the cups in the same way the old
speakers fit; in reality, you settle them in to fit against the flange that
goes around your ear. Two pieces of very thin double-back tape hold the
modules to the earcup flanges; re-mount the earseals and they hide the flange
and the edges of the modules. Put the earcups back into the frames and you're
ready to try 'em out.
Return To Service
Try Each Cup Before Final Installation...
The new cables are installed and the
wiring is about to be connected. Click image for larger version.
Once the assembly process is complete, the next step is to test your
handiwork. For this, you don't even need an airplane. Simply put a
9-volt battery in the power box, plug the power cable into the box, insert head
into headsets and throw the power switch to "on." In about a second,
you'll hear less presuming your efforts worked as well as mine. The Headsets
Inc. conversion surprised me in its effectiveness. The system worked well
enough to mute the background noise around my house.
Test One, the ANR wiring:
Success! No feedback, screeching or hissing; only muted background modulation.
Which is as it should be.
The next day, with the airplane, I plugged in the jacks, started the engine,
turned on the ANR, then a com radio and held my breath. Instantly, I heard the
highly distorted audio of a Cherokee several miles out and inbound. After
adjusting the radio and intercom volumes, I listened closely. The next call
from the Cherokee was as clear as I've heard in any headset.
Test two, a functional test: complete and equally successful!
Finally, time came to key the mic and venture a transmission; no squeal or
feedback on keying the mic ... and the Cherokee pilot answered my request for a
radio check with a hearty, "Five-by-Five, 73 Papa."
Test three and another hit; a hat trick! Everything worked!
sitting on the ground, engine at run-up rpm, talking to a guy only a couple of
miles way, everything worked. No sweat. Our first road trip with the Headsets
Inc. ANR conversion started within the hour. Now,
we'd learn whether we spent wisely, investing about $360 to upgrade our David
Clarks to ANR.
...Baptism Of Flight
than an hour after checking out both of our freshly converted David Clark
headsets, Annie and I launched on one of our routine trips east to call on
business associates and visit family. On this day, stormy weather along our
route encouraged filing IFR, which meant sharing the airways with a lot of
other pilots and controllers slightly stressed by the conditions. All the
ingredients of summertime flying were present: towering cumulus,
big storm cells scattered across 60,000 square miles of the Midwest U.S. and dozens of
commercial, GA and military aviators competing for the attention
and approval of ATC.
Wiring is connected; the new Headsets
Inc. modules are next. Click image for larger version.
A better time to hear clearly and listen to others' calls never existed.
But my satisfaction with our decision started before we left the ramp at our
home base of Augusta Municipal Airport (3AU), a few miles east of Wichita. With a storm
cell approaching from the southwest urging us on, we departed with our
clearance in hand. And we got a last-second weather update from the ATIS at
Wichita Mid-Continent Airport (ICT) while taxiing to Runway 36. Why this
out is because usually the signal is too noisy and the modulation too weak to
understand while on the ground at 3AU. Today, however, the voice came through
clearly, albeit not cleanly or strongly, thanks to the quieter environment
inside my headsets, the clearer audio and the lower volume settings on the
The static and noise remained in the signal; but the clearer audio and lack
of distortion from overdriving the headset speakers allowed the voice to stand
out from the junk more clearly.
For the first 90 minutes of our flight to Jeffersonville, Ind., I found
myself returning to the intercom and radio volumes again and again, each time
nudging down the level a little more. By the time we crossed the Mississippi
couple of hours later, the volume controls were down at the equivalent of 2.5
to 3 on a scale to 10, compared to 7.5 to 8 before the conversion. Radio calls
from controllers talking over distant repeaters came through more clearly than
they had on prior trips across this same route. In fact, it occasionally irritated
me that people were talking in the background back at Kansas City Center; irritated
me until it struck me that those voices never before came through on a center
frequency. Clearly, the conversions allowed me to hear sound masked or muffled with
the headsets in their original-equipment form.
Throughout the trip, which included some tense moments flying a localizer
approach into Leesburg, Va., the audio seemed clearer, crisper and at a lower
volume that was much more comfortable to hear.
The wiring is complete and the new
modules are connected. That pink stuff inside the earcup shell is the
sound-deadening insulation that came with the Headsets Inc. kit. Click
image for larger version.
So far, we've put more than 40 hours on our converted David Clarks and
there has been only one difference from the manufacturer's promise: We're getting about 25 to 30 hours on a battery
versus the 15 to 20 hours promised by Headsets Inc.'s
literature. Why this is the case is anyone's guess. We believe the airplane's sound insulation
makes the cabin so much quieter than average that there is less demand placed
on the ANR circuitry to produce counter noise. In other words, the units have
less work to do when cutting noise by 18 to 20 dB and don't consume as much
There is one thing I'd do differently, where I faced with doing this again
which I would, most assuredly. Just as we ordered the new main cable with its
new jacks, I'd go ahead and order power modules to install in the airplane and
save the boxes for use in other airplanes or in the event of a power problem.
The permanent connections cost another $20, plus installation in your plane. I
figure in my lifetime the savings in batteries will cover the costs.
There you have it. The path to truth, enlightenment and ANR capability
comes in a kit from Headsets Inc. near Dallas. For me, spending a lot more on
a pair of new headsets to
get no more in ANR just didn't seem smart. Don't feel handy with a soldering
iron and a set of well-written, color instructions? No problem: Send Headsets
Inc. your existing units and an extra $50 and the company will do the work for you.
As it stands, you can order kits by phone, online or at most of the major
events on the general-aviation calendar Sun 'n Fun, EAA AirVenture Oshkosh, AOPA
Expo, etc. We
ordered at Sun 'n Fun and saved about $40, making our total investment
less than $375, new cables and all. That's for two conversion kits less
than the price for one of the fancy new ANR headsets we liked best in
comfort, fit and noise attenuation and barely half the price for one of
the sets I really had my eye on buying.
Try it you'll like it. So will your ears.
|Headsets Inc. is a
long-time AVweb sponsor. However, the author neither sought nor
received any consideration from Headsets Inc. in choosing the
company's conversion kit. This article was conceived both after
purchasing the kits and without any assistance from Headsets Inc.
To learn more about the Headsets
Inc. line of conversion kits for your passive headsets and to order, be
sure to visit the company's Web site.