Date: Sun, 03 Jan 1999 20:03:32 -0600
From: Carlos Leon <services@argonaut.net>
Subject: COZY: headsets

In People's opinion.  What is the MOST CONFORTABLE passive noise
reduction HEADSETS available in the market ?

Best Regards

Date: Sun, 03 Jan 1999 23:05:45 -0500
From: Rob Cherney <cherney@home.com>
Subject: Re: COZY: headsets

At 08:03 PM 1/3/99 -0600, Carlos Leon wrote:
>In People's opinion.  What is the MOST CONFORTABLE passive noise
>reduction HEADSETS available in the market ?

I'm happy with the Peltors.  In addition, I've added the Oregon Aero
temperfoam ear seals, which makes them even more confortable than the stock
units.

Rob-

+------------------------------------------------------------------+
|Robert Cherney                      Home Phone: (410)465-5598     |
|Ellicott City, Maryland                 e-mail: cherney@home.com  |
+------------------------------------------------------------------+

From: mikefly@juno.com
Date: Mon, 4 Jan 1999 08:31:52 -0600
Subject: Re: COZY: headsets



On Sun, 03 Jan 1999 20:03:32 -0600 Carlos Leon <services@argonaut.net>
writes:
>In People's opinion.  What is the MOST CONFORTABLE passive noise
>reduction HEADSETS available in the market ?
>
>Best Regards
>
>
Peltor

Mike Bowden

From: sdbish@juno.com
Subject: Re: COZY: headsets
Date: Mon, 04 Jan 1999 12:16:52 EST


>>In People's opinion.  What is the MOST COMFORTABLE passive noise
>>reduction HEADSETS available in the market ?
>>

After several years in the AF flying the big birds and wearing headsets, 
I personally had no problem with any brand, as long as if fit tight and
shut out noise.   My wife got me David Clark, with which I'm quite
comfortable.
On the other hand,  my wife has trouble with anything on her head.    She
tried various types, including Telex and straight stereo headsets
adapted,  but was bothered by the clamping force after only short
durations.  Eventually the opportunity arose for her to try Peltor,  and
she was surprisingly satisfied, and greatly extended the time she would
wear them.   Peltor would definitely be her recommendation from someone
who is quite sensitive to something on her head.

Marv Bishop

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Date: Mon, 04 Jan 1999 09:57:28 -0800
From: Frank Johanson <ics@ime.net>
Subject: Re: COZY: headsets



Carlos Leon wrote:

> In People's opinion.  What is the MOST CONFORTABLE passive noise
> reduction HEADSETS available in the market ?
>
> Best Regards

  Dear Carlos,

We found that one of the best things to do for our headsets is the
sunglasses.  The headset was pressing on the stems of the glasses
causing a lot of discomfort.  We purchased glasses from Zurich
International, 500 Cohasset Road, Suite #34, Chico  CA  95926  (USA) ,
phone number (916) 893-3657.  They have a headband that can go in place
of the earpieces (disattaches easily).  This was great!

To date we have bought several pairs each since we use them all year
round.  We keep a pair in the bag for our headsets and a couple pair in
the cars.  (Snow is a major brightness factor when driving around here
in Maine).

We bought our glasses at Oshkosh initially about 4 years ago.  We have
talked to them when we needed to replace stems, & ordered a pair.  We
then bought two more pair & the bands at OSH this summer.  What a
difference flying to OSH and flying home!

Good Luck,

Frank Johanson

PS:  We have a SoftCom  Passive Noise Headset and 2 FliteSoft ANR
headsets.  When the plane is done, we will use those for the back seat &
get new Boise for the front.  Also, the Gel cushions are far superior to
the foam ones.  They can be bought searately and changed.

Date: Sat, 08 May 1999 09:52:50 -0500
From: David Domeier <david010@earthlink.net>
Subject: COZY: Noise cancel headset??

    Some of you guys must be using a noise cancelling headset.  I'm in
the market for one but don't know much about which is best for the buck.

    How 'bout sharing your opinion if you've got one.

dd

From: "John Slade" <rjslade@bellsouth.net>
Subject: Re: COZY: Noise cancel headset??
Date: Sat, 8 May 1999 11:50:36 -0400

David,
I have the new Pilot DNC. Its superb. No boxes or external batteries. So
good that I was getting the rpms wrong for a couple of hours while I got
used to the reduction in noise. A freind had the same model and it died. He
sent it back and they replaced it by return mail.
John Slade


From: cdenk@ix.netcom.com
Date: Sat, 8 May 1999 11:25:03 -0500 (CDT)
Subject: Re: COZY: Noise cancel headset??

On 05/08/99 09:52:50 you wrote:
>
>    Some of you guys must be using a noise cancelling headset.  I'm in
>the market for one but don't know much about which is best for the buck.
>
>    How 'bout sharing your opinion if you've got one.
>
>dd
>
>
>

I have 3 of the original BOSE active noise cancelling, and are quite happy with them. After a long flight our ears are fine, 
and we talk in normal volume. Several years ago we tried the updated BOSE series II, and liked them, and put them on the low 
priority money list. At OSH last time we tried the BOSE series X. THe ear cups were more comfortable, and I believe the 
accoustics and noise canceling to be better, and the size is smaller. But the design of the headband has a spring loaded joint 
at the top of the cranium. The padding is poor, and is not comfortable, as a result they are not on our money list at all!.

I fly with a friend safety pilot in a nice Mooney. He has experimented with just about every headset that is out there, 
spending more money than the Bose would cost. I prefer the Bose to all he has had, but my built-in interfaces aren't portable. 
When he's safety pilot in the Cosy, he used to bring his headset along, but now he uses the Bose.

Date: Sat, 08 May 1999 09:37:44 -0700
From: Jeff Burhans <orion13@primenet.com>
Subject: Re: COZY: Noise cancel headset??

>     How 'bout sharing your opinion if you've got one.

Sure! I'm still a student pilot flying C150's, but I *LOVE* mine. I've got a
SoftComm Phoenix (Model C-20) headset. I've used a bunch of different
headsets (as a student of course, it's catch as catch can!) including some
noise cancelling ones, and others not - this one is the most comfortable and
clearest headset I've ever used.It does take a bit of getting used to as the
engine noise is muted from what I was used to on the non-NC's, but that only
took a flight or two....

    Hope this helps some!

    *
   * *RION
    *



Date: Sat, 08 May 1999 20:15:00 -0400
From: John <n69cz@usa.net>
Subject: Re: COZY: Noise cancel headset??

Hi Dave,
    I just bought a pair of Flight Com's ANR6  noise canceling headsets for
$375.00 each from:  http://www.airsource1.com
I like them and the price is right.
John Vermeylen
N69CZ

David Domeier wrote:

>     Some of you guys must be using a noise cancelling headset.  I'm in
> the market for one but don't know much about which is best for the buck.
>
>     How 'bout sharing your opinion if you've got one.
>
> dd


From: Jim Hocut <jhocut@mindspring.com>
Subject: RE: COZY: Noise cancel headset??
Date: Sat, 8 May 1999 21:30:47 -0400

I've had a question about noise cancelling headsets.  I've never had 
the pleasure of trying any, so far my trusty David Clark's work just 
fine.  What I've wondered is if noise cancelling headsets do such a 
good job of getting rid of noise you don't want to hear, wouldn't 
they also get rid of airplane noises that you really do want to hear. 
 For instance, while instructing in a 172 a couple years ago on a 
dual cross country we started hearing a high pitched squeel from up 
front.  The engine guages weren't showing anything wrong, but we 
elected to land at the nearest airport just to be safe.  Once on the 
ground it was apparent we had made a good decision since the engine 
was spilling oil at an alarming rate because the seal for the 
generator shaft had torn up.  Without having heard that noise we'd 
have been landing in pine trees miles from anywhere instead of at an 
airport.



Jim Hocut
jhocut@mindspring.com



From: cdenk@ix.netcom.com
Date: Sat, 8 May 1999 20:51:33 -0500 (CDT)
Subject: RE: COZY: Noise cancel headset??

I was concerned with hearing important noises. I have on occasion lifted an earcup, or turned off the noise cancelling to 
check, and several times had noises occur (once was a magneto bearing inner race spinning on the shaft)  that I had no problem 
hearing. I was warned about not hearing noises when I first started flying, kept an awareness. There are some noises you can 
hear better with the ambient blocked patially. I don't think it is a concrern with the first series Bose, or most others. I 
have had a mag go out, a fuel injector nozzle clog, a swallowed valve, and a prop bade split almost to the hub, a vaccum 
pump failure and I can assure in every instant, I had no problem noticing something was wrong almost instantly. There is a 
difference in sound, and its notieable.

From: "John Slade" <rjslade@bellsouth.net>
Subject: Re: COZY: Noise cancel headset??
Date: Sat, 8 May 1999 22:29:24 -0400

Jim,
>wouldn't they also get rid of airplane noises that you really do want to
hear.
Marc Zeitlin (works for Bose) can probably answer this one better than me,
but...
I don't think so. You still hear all the noises. They're just not as noisy.
Think of it as reducing a shout to a normal conversational volume. You
actually hear it better. Makes distinguishing modulated tones (controller
etc.) much much easier.
Borrow one & try it. It might stop you getting tinnitus.
I have even been known to use my DNC headset when mowing the lawn. Now if I
could just get piped music...  hmmm...
John Slade

Date: Sun, 09 May 1999 08:41:58 -0500
From: David Domeier <david010@earthlink.net>
Subject: Re: COZY: Noise cancel headset??

John,

    Thanks to you, Carl, Jeff, and all for the info.

    My current Telex units are 19 years young, still work, but capture
every sound very efficiently and seem to make it louder.  At 160 KIAS I
can not talk to ATC.  All they hear is airplane noise.  I have to say
"Standby while I slow up to Cessna speed".

    Re my engine break-in:  yesterday I climbed to 12,500' from take off
without an overheat.  OAT at take off was 71.  The engine is definitely
cooling down.  Does anyone know a clew as to when the rings are properly
seated?  There sure is a lot of opinion on the subject but nothing
definitive.

dd

From: cdenk@ix.netcom.com
Date: Sun, 9 May 1999 08:45:56 -0500 (CDT)
Subject: Re: COZY: Noise cancel headset??

was said Marc Zeitlin (works for Bose) can probably answer this one better than me,
but...>

Remember Mark is a mechanical engineer, you know stress, strains, forces, chasing things you can usually see, not electrons 
running around inside wire.


From: Lee810@aol.com
Date: Sun, 9 May 1999 11:34:43 EDT
Subject: Re: COZY: Noise cancel headset??

In a message dated 5/9/99 7:50:38 AM Mountain Daylight Time, 
cdenk@ix.netcom.com writes:

> was said Marc Zeitlin (works for Bose) can probably answer this one better 
> than me,
>  but...>
>  
>  Remember Mark is a mechanical engineer, you know stress, strains, forces, 
> chasing things you can usually see, not electrons 
>  running around inside wire.

Actually,  Marc, whose major pet peeve is people spelling his name with a 'k' 
instead of a 'c', is formally trained as an Aerospace Engineer (from MIT, no 
less) but he's probably the best ME I met at HP.   (Carl, when you quote from 
text that has his name spelled correctly and you misspell it ... all I can 
say is that I hope he doesn't kick you off the list :-).

Acoustics and vibrations _are_ the domain of MEs so I'm sure Marc would give 
us all enlightenment if he didn't feel there might be a conflict of interest 
since he now works for Bose.   

I am a licensed EE and I can tell you that I know very little about the world 
of active noise cancellation.  It's conceptually very simple, but I'm sure to 
put it to practice, it's frighteningly complex.

As for the original questions about hearing the high pitch squeal, remember 
that ANR headsets do all their work below 300 Hz and a squeal is _well_ above 
that range.  Above 300 Hz they rely on the passive components like foam to 
dampen the sound and that works the same as a regular headset.  

Missing audible cues from an engine that is misbehaving is a topic comes up 
so regularly it might make sense to commission a study to see if ANR headsets 
work as well or better than conventional headsets in allowing you to detect 
these acoustic anomalies.

Lee Devlin

Date: Sun, 09 May 1999 12:58:22 -0400
From: bil kleb <w.l.kleb@larc.nasa.gov>
Subject: Re: COZY: Noise cancel headset??

cdenk@ix.netcom.com wrote:
> 
> At OSH last time we tried the BOSE series X. [..] The padding is poor, and is
> not comfortable [...]

mary tried them this spring: they went back before the 30 days were up.
noise reduction was superb; comfort was lacking.

-- 
bil <mailto:w.l.kleb@larc.nasa.gov>

From: cdenk@ix.netcom.com
Date: Sun, 9 May 1999 15:52:37 -0500 (CDT)
Subject: Re: COZY: Noise cancel headset??

My apology to Marc, for misspelling his name, spelling hasn't been my greatest claim to fame. When I was in 1 or 3 grade area, 
my name was quite a teasing point, where the kids, including the class bully had much fun. I quickly learned to be very 
tolerant. 

Also if I was out of place with Marc's M.E., wasn't thinking of accoustics, all the M.E.s I deal with are either machine 
design or HVAC. Of course we could go back in history when there was only 2 types of engineers, military and civil, with the 
mechanicals and the electricals branching off near the beginning.

Agree with the comment mic near the lips. The Bose does a very good job of enabling a clean transmission, they have light foam 
wind muffs that I secured with a small black tyrap.

Re: high pitched squeel, thanks for reminding me that when the sould waves get short, its literally impossible to do any 
correction with the active, its all passive. In that case, you would hear the high pitch more easily since the low pitches are  
antenuated. 

Date: Mon, 10 May 1999 08:55:08 -0400
From: Paul Krasa <p.w.krasa@larc.nasa.gov>
Subject: Re: COZY: Noise cancel headset??

I have two different types of ANC headsets in my flight bag.  Two headsets
were converted using the kits advertised on Sport Aviation; the other one
is a Lightspeed 20K.  

The Lightspeed is superior in noise canceling and comfort to the converted
headsets, but not by much.  I borrowed friends noise canceling headsets
(Bose, David Clark, Telex, and Lightspeed).  I choose the Lightspeed
because it was the most comfortable and had as good of noise canceling as
the others.  My non calibrated ears could find little difference in the
quality of the noise canceling, but I could tell the difference between a
15db ANC headset and a 20db ANC while flying.  Another issue to consider is
headset clearance to the canopy.  If you are tall like me, the one Inch of
head clearance will be the foam pad at the top of some of the new headsets.
 One of the reasons I bought the Lightspeed instead of the Bose, is I had
to bend my neck to close the canopy of my Long Ez.  Not a situation
conducive to flying.

If you already have a headset you like, convert it over to ANC.  The
conversion takes less than an hour per headset.  I have converted over a
number of friends headsets, and can now do one in about a half hour.  The
difference between my converted headset and my Lightspeed 20K is comfort.

Paul
Long EZ 214LP

p.s. Project Status:  High speed taxi is going well.   A few growing pains
here and there, but nothing major.  Just about ready for the "big one."
Weather has been the big delaying factor has been either IFR or winds in
excess of 10kts.  Yesterday morning the winds were calm, and I was able to
"fly" the canard down the runway, and held the same attitude for the whole
run.  Next, wing rocks with the canard flying.






At 09:52 5/8/99 -0500, David Domeier wrote:
>    Some of you guys must be using a noise cancelling headset.  I'm in
>the market for one but don't know much about which is best for the buck.
>
>    How 'bout sharing your opinion if you've got one.
>
>dd
>
>
>

Date: Sun, 9 May 1999 11:28:17 -0400
From: Bill Theeringer <Composite_Aircraft_Accessories@compuserve.com>
Subject: COZY: Microphone noise

 ....... All they hear is airplane noise.  I have to say
"Standby while I slow up to Cessna speed".


Dave and all;

I am using the Bose series I, but before that I had the stock David Clarks.
 I have 2 ham stations on board, world wide HF and 300 mile radius VHF.  I
am routinely complimented on the excellent quality of my transmitted audio
by other amateurs (as well as controllers) who are lifetime radio
operators.  Most are amazed to find out that I am in an airplane.  There is
a secret to having this quality of transmitted audio.  The secret is to
minimize the signal to noise.  Signal being defined as your voice and noise
being everything else.  I went through considerable testing to arrive at an
optimum combination and it worked out to be the following:

Turn the mike gain control on the back of the mike down as low as it will
go.  Add a 27 ohm resistor across the mike lead to ground.  This can
probably best be done inside the plug, although I did mine in the panel. 
ALWAYS have the mike virtually touching your lips and at an angle to the
side.  If the mike moves one inch away your voice will be very weak.  As
weak as the background noise you have just minimized.  I used resistance
and capacitance decade boxes while flying to arrive at the best combination
while communicating with a local blind ham (a piano tuner) for the best
results.

Bill Theeringer
N29EZ

See our award winning Long EZ with 
Jim Newmans excellent retractable gear at  
http://www.flash.net/~infaero/infgear.htm

Composite Aircraft Accessories
PO Box 21645 Santa Barbara, CA 93121
HOME:  805-964-5454, SHOP:  805-964-5453

Date: Mon, 10 May 1999 22:25:40 -0400
From: "Marc J. Zeitlin" <marcz@ultranet.com>
Subject: COZY: Noise reduction headset functionality

Lee Devlin wrote:

>Actually......

Thanks, Lee, but if I got bent every time someone misspelled my name (Marc
OR Zeitlin), I'd be a basket case by now :-).

>Acoustics and vibrations _are_ the domain of MEs so I'm sure Marc would give 
>us all enlightenment if he didn't feel there might be a conflict of interest 
>since he now works for Bose.   

I thought Carl's comment was a bit strange, but I can certainly understand
the sentiment.  I'm NOT an acoustic engineer (and don't play one on TV),
but I have learned a lot about ANR headsets during my 10 months here at
Bose.  I'll be happy to expound on the theory and practice, and I'll keep
the advertisements to the "zero" level asked for in the Charter.

>As for the original questions about hearing the high pitch squeal, remember 
>that ANR headsets do all their work below 300 Hz and a squeal is _well_ above 
>that range.  Above 300 Hz they rely on the passive components like foam to 
>dampen the sound and that works the same as a regular headset.  

This is basically correct.  ANR technology (ANYONE'S - not just Bose's)
works by placing a microphone inside the earcup and listening to the noise
that gets through to the inside.  An attempt is made to place the
microphone as close to the ear as possible (without actually putting it
inside the ear, although that has been attempted also) so that it will
"hear" just about what the ear does.  The electronics then take that
signal, create a signal equal but 180 degrees out of phase (the opposite
"sound", in other words) and then pipe that back through the speaker
(driver, or transducer, in technical terms).  Since the driver produces
sound waves equal and opposite to the "noise", the noise is cancelled out.
The NAV/COM/Radio signals are passed through the driver without being
cancelled, so you still hear them clearly.  That's the theory, anyway.

In practice (as Lee points out) this only works at the lower frequencies -
from 10 Hz up to the low 100's of Hz - I believe our ANR starts rolling off
(becoming less effective) around the 200 Hz point, maybe a bit lower.  As
the frequency rises and the sound waves get shorter, it's less possible to
cancel the noise by sensing with a microphone that isn't IN the ear - the
"sound" produced by the driver will do a very good job of reducing the
noise exactly at the microphone, but not so good of a job at the ear (which
is, of course, what WE care about :-) ).

Now, in any case, the "cancellation" is not perfect, hence the term "noise
reduction", not "noise cancellation".  Good ANR headsets can reduce the
noise level by 15 - 20 dB or so in the frequency range described (varies by
design and by frequency).  Since it is the lower end of the frequency range
that does the most to interfere with communication intelligibility, this is
the range that is most important to cancel (not to mention the damage that
it does to your inner ear).

One problem that can occur in very loud aircraft is that the "driver" in
the earcup is trying to create as much noise (but opposite) as is getting
in the earcup.  At high sound pressure levels, the driver will "clip" (just
like your speaker at home, when you turn up the volume too loud to listen
to the Grateful Dead :-) ) and it will create nasty cracks, pops, and other
noises.  One difficult issue in designing these headsets is trying to
mitigate this problem and have the headseat gracefully stop cancelling
noise, without making it too obvious.

It is also critical for any ANR headset to have an excellent seal against
the head.  Hair, glasses, hats, big ears, misadjustments, sweat, etc. can
have large effects on the quality of noise reduction.

As far as PASSIVE noise reduction goes, all headsets work about the same.
Create a large airspace around the ear, keep as much sound out as you can
with a seal, and absorb the high frequency energy that does get in with
some absorbent material - usually foam or the equivalent.  For the most
part, the larger the enclosed space, the better.

So, what was the question again? :-).  In your standard Cessna 150 or
functional equivalent, the noise in the earcup at the ANR frequencies will
be in the 100 dB range, so that after reduction, the noise will be in the
80 dB range.  This is much lower, but far from inaudible - actually, it's
still pretty loud.

I think that it is highly improbable that (with the current crop of ANR
headsets, or into the forseeable future) any noise would be reduced to the
point that it would be inaudible, or even hard to hear.  It will just be
less painful.  At passive frequencies (those above 200 Hz or so), the noise
reduction is also in the 20 dB range, so the same comments apply.  As Lee
stated, squeals are at higher frequencies, while the lower frequencies
include rumbles, propeller resonances, etc.

If it were ever possible to reduce the noise levels to the 60 dB range or
below, the concern over missing noises might be reasonable (like missing
your oil pump bearing failing in a Cadillac).  I'm not holding my breath
until this level (20 dB lower than present, both in ANR and passive
frequencies) is attained :-).

With respect to comfort (Carl and bil both remarked on it), all I will say
is that this is extremely personal, and I would recommend that you not buy
ANY headset (active or passive) without trying it, at least for a few
hours, and preferably for the 30 day period that more than a few of the
manufacturers now offer.  Also, different headsets fit differently and use
more or less headroom.  You just have to try them out to see if they work
for you.

--
Marc J. Zeitlin           mailto:marcz@ultranet.com
                          http://www.ultranet.com/~marcz/

Date: Sat, 14 Aug 1999 16:27:52 -0400
From: Gregg Perry <gperry@usit.net>
Subject: Re: COZY: ANR Headsets



cdenk@ix.netcom.com wrote:

> Comfort is part of the picture. How is your hearing protected, difficult to measure, but one unscientific way is after a 4
> hour flight, do you speak in normal volume to the line boy when getting gas. The Bose allows that.

Carl,

1) Look up the word "subjective" in the dictionary
2) Reread my post.
                                Gregg Perry


