[ARC5] German throat mics - mystery almost solved
Richard Knoppow
1oldlens1 at ix.netcom.com
Fri Dec 4 10:37:13 EST 2020
I pretty much agree with this. Probably the most thoroughly
designed mechanism was the Bell System 500 series telephone. Of
course, that used a carbon microphone (or transmitter if you
prefer) where these days superior performance at lower cost can
be had with an electret. The requirements for a cell phone are
far different from those for a land line phone like the 500. In
those days the telephone company was concerned with both the
quality of the reproduction, since they were selling
communication, and the economics of the telephone, which was
considered a part of an integrated system. Its ability to work at
low levels and deliver high levels was important as was its
projected life. Until changed by regulation the instrument
belonged to the phone company who had an interest in its lifetime
and cost of maintenance. Cell phones are very different. I
recently got a new cell phone and found the audio quality was
better than my old one. I have damaged hearing so I can't
compensate much for a poor phone.
Bell Labs did an enormous amount of testing to determine the
nature of speech and hearing and how to maximize articulation. It
was directly concerned with their business. Lots of research was
done elsewhere as well, such as at Harvard and other universities.
On 12/4/2020 5:04 AM, Michael Hanz wrote:
> Well, perhaps there was a tiny nugget of wisdom in the satcom
> phone test, though the issue was not necessarily the earphone
> element per se. Sometimes I reflect on how much we have lost
> since the arrival of the cell phone. Has anyone in this august
> audience compared voice quality of a conversation on your cell
> phone to that of a landline conversation between two older dial
> phones? The silly ad a few years ago of an engineer wandering
> about, saying, "Can you hear me now" rings in my mind... We
> still have a landline and two older such phones on the house
> line. Bell used to pride itself in the quality of its voice
> reproduction back in the day. Now, referring to the worldwide
> industry at large, apparently not so much. Oh, how have the
> mighty fallen... We have become accustomed to mediocrity for
> the sake of convenience.
>
> If you look deeper into that link on my website, you'll see a
> section on the importance of fit between the earphone element
> and ear, featuring the M-201 "Harvard Socket" cushion. How can
> you achieve that goal with today's stylish cell phone? It's a
> variation on the old Miller "Tastes great - less filling"
> debate, only with cell phones, it's "Looks great - sounds
> terrible."
>
> And yes, I have achieved the advanced age of a well established
> curmudgeon.
>
> - Mike KC4TOS
>
> On 12/4/2020 7:19 AM, Mike Feher wrote:
>>
>> It was for a small manpack SATCOM terminal. I knew the design
>> inside out. Regardless, in the qualifications matrix in the
>> spec., this was marked “test”, probably by some idiot who
>> copied another spec., to put this spec. together, so it had to
>> be done. I believe the score was 100%. It was a waste of
>> resources. The program was finally cancelled due to massive
>> budget over runs. Later it was recompeted, the test was not
>> included in the new spec.
>>
>> Mike B. Feher, N4FS
>>
>> 89 Arnold Blvd.
>>
>> Howell NJ 07731
>>
>> 848-245-9115
>>
>> -----Original Message-----
>> From: arc5-bounces at mailman.qth.net
>> <arc5-bounces at mailman.qth.net> On Behalf Of Richard Knoppow
>> Sent: Friday, December 4, 2020 12:07 AM
>> To: arc5 at mailman.qth.net
>> Subject: Re: [ARC5] German throat mics - mystery almost solved
>>
>> Maybe not such a waste as you suggest. You have not given
>> us any details of why the tests were made or what was being
>> tested.
>>
>> Articulation and intellibibility testing is common in
>> audiology but was of considerable value in testing
>> microphones, headphones, signal processing and other aspects
>> of communication. Bell Labs had a list of test words. I think
>> it is published in the BSTJ and in some texts. So, what was
>> being tested there?
>>
>> On 12/3/2020 8:32 PM, Mike Feher wrote:
>>
>> >
>>
>> > Interesting comment Mike. Back about 20 years ago I was
>> witnessing a
>>
>> > test, run by a contractor for the Military, where speech
>>
>> > intelligibility was performed. They hired around 20 random
>> people from
>>
>> > the street for a few hours. There were two rooms and the
>> group was
>>
>> > split in two, half in each room. One group was each given a
>> list of
>>
>> > words to speak into a mike and the people in the other room
>> had to
>>
>> > write down what they heard.
>>
>> > After that, the groups switched rooms and the test was
>> repeated. They
>>
>> > were then released and the results scored. I actually
>> thought the
>>
>> > whole exercise was hilarious and a waste of government
>> funds. 73 –
>>
>> > Mike
>>
>> >
>>
>> > Mike B. Feher, N4FS
>>
>> >
>>
>> > 89 Arnold Blvd.
>>
>> >
>>
>> > Howell NJ 07731
>>
>> >
>>
>> > 848-245-9115
>>
>> >
>>
>> > *From:* arc5-bounces at mailman.qth.net
>> <mailto:arc5-bounces at mailman.qth.net>
>>
>> > *On Behalf Of *Michael Hanz
>>
>> > *Sent:* Thursday, December 3, 2020 11:18 PM
>>
>> > *To:* MARK DORNEY <mkdorney at aol.com
>> <mailto:mkdorney at aol.com>>; Hubert Miller
>>
>> > <Kargo_cult at msn.com <mailto:Kargo_cult at msn.com>>
>>
>> > *Cc:* arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>;
>> milsurplus <milsurplus at mailman.qth.net
>> <mailto:milsurplus at mailman.qth.net>>
>>
>> >
>>
>> > Well, the science of larynx mics was pretty well investgated
>> even
>>
>> > before the war began, and more intensively in the early part
>> of the
>>
>> > war. I always remember with amusement the Bell Labs report
>> that said,
>>
>> > "[the throat microphone] would probably have been a very
>> effective
>>
>> > instrument but for the fact that the speech signal available
>> at the
>>
>> > larynx is intrinsically unintelligible." (Page 131 at
>>
>> > https://aafradio.org/docs/NDRC_Division_17_excerpts.pdf
>> <https://aafradio.org/docs/NDRC_Division_17_excerpts.pdf>
>>
>> > <https://aafradio.org/docs/NDRC_Division_17_excerpts.pdf
>> <https://aafradio.org/docs/NDRC_Division_17_excerpts.pdf>> )
>>
>> >
>>
>> > In sophisticated word articulation tests, the low percentage of
>>
>> > success rates were significant. Fortunately, the move to higher
>>
>> > altitudes encourage mask mics, so the throat mics began to
>> die out
>>
>> > through disuse and more modern hands free mics like the
>> M5A/UR boom
>>
>> > mic originated by the Navy.
>>
>> >
>>
>> > - Mike KC4TOS
>>
>> >
>>
>> > On 12/3/2020 9:01 PM, MARK DORNEY via ARC5 wrote:
>>
>> >
>>
>> > I wonder if the Germans had better luck with their throat
>>
>> > mics than the US had with theirs. While never fully
>>
>> > eliminated from USAAF use, they were replaced by better
>>
>> > mask mics and even the T-17 lollipop mic because hardly
>>
>> > anybody could understand what the hell was being said when
>>
>> > the throat mic was used. But it’s use sure looked good in
>>
>> > the movies.
>>
>> >
>>
>> > Mark D.
>>
>> >
>>
>> > WW2RDO
>>
>> >
>>
>> > “In matters of style, float with the current. In matters of
>>
>> > Principle, stand like a rock. “. - Thomas Jefferson
>>
>> >
>>
>> > Sent from my iPhone
>>
>> >
>>
>> >
>>
>> >
>>
>> > On Dec 3, 2020, at 6:20 PM, Hubert Miller
>>
>> > <Kargo_cult at msn.com <mailto:Kargo_cult at msn.com>>
>> <mailto:Kargo_cult at msn.com <mailto:Kargo_cult at msn.com>> wrote:
>>
>> >
>>
>> >
>>
>> >
>>
>> > I'm going thru my stuff and picking out downsizing
>>
>> > candidates, and found a German
>>
>> >
>>
>> > 'throat microphone', but with a 5 pin connector, so not
>>
>> > Panzer. The strap has only
>>
>> >
>>
>> > the number L38114, so on a lark, I decided to try to
>>
>> > look this up. Lo and behold, an
>>
>> >
>>
>> > "Online Throat Microphone Museum",
>>
>> >
>>
>> > http://beatboxmics.com/#!/pages/museum
>> <http://beatboxmics.com/#!/pages/museum>
>>
>> > <http://beatboxmics.com/#!/pages/museum
>> <http://beatboxmics.com/#!/pages/museum>>
>>
>> >
>>
>> > Who would have thought?
>>
>> >
>>
>> > <image001.png>
>>
>> >
>>
>> > I learned this:
>>
>> >
>>
>> > "Abfragegarnitur L38 - Luftwaffe headset with throat
>>
>> > microphone and single receiver.
>>
>> >
>>
>> > All parts have special codes starting with "L38".
>>
>> > Throat microphone L 38114 is exactly the same
>>
>> >
>>
>> > as Kmf.b tank throat microphone. Luftwaffe production
>>
>> > control marks are all around
>>
>> >
>>
>> > (BAL = Bau Aufsicht Luftfahrt). The 5-pin connector is
>>
>> > of the type widely used by German
>>
>> >
>>
>> > Wehrmacht for telephone equipment. Maybe such "L38"
>>
>> > headsets were in use at
>>
>> >
>>
>> > Luftwaffe telephone switchboards."
>>
>> >
>>
>> > That seems likely. Anyway, the mystery of what this
>>
>> > item was, is solved. Also I had looked
>>
>> >
>>
>> > at German tubes for many years and never knew what
>>
>> > "BAL" referred to. How about that !
>>
>> >
>>
>> > I have a Swedish "Ericsson" throat mic this museum
>>
>> > doesn't know about. I wonder if it was
>>
>> >
>>
>> > supplied to the German Luftwaffe during WW2 or just
>>
>> > prior to the war. Sweden did trade
>>
>> >
>>
>> > with Germany until the point they saw Germany was on
>>
>> > its last legs and no longer presented
>>
>> >
>>
>> > a threat of taking their country.
>>
>> >
>>
>> > -Hue Miller
>>
>> >
>>
>
--
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL
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