I set up my KM-140s on a stand in my living room, about 4ft high in an ORTF pattern. I recorded 'Signs of Life' from the Pink Floyd commercial (store bought) CD 'A Momentary Lapse Of Reason'. I turned up my stereo as loud as I felt I could get away with (without the neighbors complaining). I ran the Neumanns into the mic inputs of my DA-P1 and recorded about a 3 or four minute test. I couldn't hear anything obviously wrong with the sound, which made me feel a little better.
I got this reply from Neumann in Germany:
( I did gently shake it a bit and nothing rattles so I guess nothing is broken inside. The front diaphragm also looks undamaged.)
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things to do, for a quick mechanical check:
1. anything rattling inside?
> needs to be taken apart and checked in service
2. looking at the front side, does the diaphragm, or what you can see
through the holes, still look well-tensioned, or can you see "waves" on the
diaphragm?
> probably terminal damage; probably increased bass sensitivity
3. are the rear-entry slits damaged?
> can lead to a lop-sided cardioid pattern. Might be hardly
noticeable, can also result as severely lop-sided.
Regarding sonic damage, the most effective thing to do is to direct-compare
it with your other KM140s, checking for relevant differences in
a. overall sensitivity
b. bass response
c. high treble response
d. in case of rear-entry slit damage: lateral sensitivity (hold the mic at
90°, and rotate while speaking into it. Does the sound / sensitivity
change)
If this comparison test doesn't produce any relevant differences, you
should be safe to assume that nothing has gone wrong.
If still in doubt, sending the mic in for a service check would be the
alternative.
Let's hope for the best, and good success!
Martin Schneider
(Mic Development)
Georg Neumann GmbH l Ollenhauerstr. 98 l 13403 Berlin l Germany