[ARC5] German throat mics - mystery almost solved
Scott Robinson
spr at earthlink.net
Fri Dec 4 11:02:15 EST 2020
About earphones and intelligibility: early in WWII< acoustician Leo
Beranek (for whose later formed company I used to work) was hired to
fix the inability of pilots in WWII bombers to hear the radio. First
notion was to quiet the cockpit, but that was going to be very hard to
do, what with four 2,000 HP or so engines and their propellors so close.
But Leo figured out that the terrible disc-and magnet-the kind
associated with crystal sets-were the problem. Thus was born the ANB-H1A
headset, with good sealing ear cushions and much better transducers, and
it solved the problem without modifying the aircraft or adding weight.
I used surplus ANB-H1A phones for stereo music in the 1950s, and they
sounded pretty good.
Blasts from the past, indeed.
Regards,
Scott
On 12/4/20 7:37 AM, Richard Knoppow wrote:
> 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.
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