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Re: Microphone risk factors

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On 5/12/2017 10:08 AM, Michael Kellett wrote:
> OK - I finally get what you are after but I'm not that interested in
> playing -
> I spent a fair chunk of my early engineering career designing and making
> microphones and that branched out into accelerometers and from there we
> moved into making knock sensors and supension control systems and then
> to shock recorders and then the company went bust (15 years ago) and I
> do other stuff now.
>
> If I had a really good off the wall idea about using microphones I
> wouldn't share it here :-)

You'll note I've not shared any of mine!  :>

> But - more seriously - the question is just too open.
>
> The only slightly novel thing I've considered recently is using some
> cheapo ST MEMs mics with a frequency response up to 40kHz+ to make an
> anemometer.

I'm not looking for ideas as to how to use them.  I'm looking for
general information of their vulnerabilities, contraindicators, etc.

E.g., I might come up with a great application but not be able
to find an (affordable!) device that could operate in the constraints
that the application dictates without damaging the "transducer".

So, I'm more looking for things like:
- microphones don't like getting wet
- microphones don't like being subjected to prolonged periods of high heat
- microphones subjected to frequent mechanical shock fail prematurely
- microphones don't like rapid temperature cycling
etc.

The "typical" way of thinking of microphones is in conjunction with
a human-oriented activity.  So, they are specified for "human occupied
environments" and applications that are more related to human hearing
than as general purpose transducers.

E.g., I've a buddy with a recording studio who can tell me why each
particular microphone is best suited (dollars vs. effectiveness)
for each "sound source".  But, completely helpless to tell me how
those evaluations would change if I tweaked the environment:
     "What if I wanted to record a saxophone playing in a freezer?"

I don't want to pick a mic technology only to find that the common
knowledge about it is useless outside of that *typical* application
frame.  Or, even approach a problem with an "audio" sensor if there
are NO technologies that are suitable!

For example, when tablets are manufactured (by compressing "powdered
granulation"), a common problem is air becoming entrapped in the
"powder" as it is compressed.  When the pressure is released, the
compressed air causes the tablet to "explode" (the top pops off).

This could be sensed audibly by locating a microphone adjacent to
the tablets' path of motion and listening to the sound that accompanies
the release of the compressive force (heavy filtering but you *know*
what the fundamental frequency of the signal is, a priori).

But, it would be an impractical environment as the inevitable accumulation
of the powdered "granulation" would quickly render the microphone
("acoustical transducer") useless.

You'd never encounter this problem in a more traditional microphone
application!  :>

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Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-10 21:27 -0700
  Re: Microphone risk factors Phil Allison <pallison49@gmail.com> - 2017-05-10 21:39 -0700
  Re: Microphone risk factors jrwalliker@gmail.com - 2017-05-11 07:01 -0700
    Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-11 11:06 -0700
      Re: Microphone risk factors piglet <erichpwagner@hotmail.com> - 2017-05-12 09:02 +0100
      Re: Microphone risk factors "Michael Kellett" <nospam@invalid.com> - 2017-05-12 16:02 +0100
        Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-12 09:37 -0700
          Re: Microphone risk factors "Michael Kellett" <nospam@invalid.com> - 2017-05-12 18:08 +0100
            Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-12 11:02 -0700
              Re: Microphone risk factors Phil Allison <pallison49@gmail.com> - 2017-05-12 17:44 -0700
              Re: Microphone risk factors Terry Newton <nbill@bellsouth.net> - 2017-05-13 17:19 +0000
                Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-13 11:57 -0700
                Re: Microphone risk factors Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-13 19:12 +0000
                Re: Microphone risk factors Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-14 08:40 +0000
                Re: Microphone risk factors Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-14 09:17 +0000
                Re: Microphone risk factors Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-05-14 10:49 +0000
                Re: Microphone risk factors Terry Newton <nbill@bellsouth.net> - 2017-05-13 19:26 +0000
                Re: Microphone risk factors (OT -- long) Don Y <blockedofcourse@foo.invalid> - 2017-05-13 13:37 -0700
            Re: Microphone risk factors "dcaster@krl.org" <dcaster@krl.org> - 2017-05-13 11:06 -0700
              Re: Microphone risk factors Don Y <blockedofcourse@foo.invalid> - 2017-05-13 12:11 -0700
              Re: Microphone risk factors krw@notreal.com - 2017-05-13 20:36 -0400

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