Hey David. Well, that's a horse of a different color. I could see how the old push and pull could not be healthy for a delicately mounted diaphragm.

I'm no expert on how microphones are built or what physical conditions they will withstand: I just use the ones I have available to me and spend too much time reading specs online about ones I'm not going to be able to afford anyway!
S'b'B

david is exactly right
the pressure added by pulling and pushing is
way higher than the sound the reeds make in the box
and it;s not even sound, it;s so low, it;s almost
like DC the air
the mics don;t like it
if the mics pass it, the amps won;t like it
if the amps pass it, the speakers won;t like it

dynamic mics [at least cardioid ones] can
handle this because their elements are ported
on both sides of the diaphragm, and these
DC pressures can equalize on both sides, causing
no net movement and no current from the DC

you might find a cardioid condenser mic that
works like that but why? the dynamic mics sound
good

although, condenser mics are usually smaller
which is good in a cramped 3 row

i managed to find some fairly small dynamic elements
you could try
i have a ton of them, like 40
they are about 3/4" deep

wle.

Larry explained it exactly right.

The first time I tried to put a condensor inside an accordion, it sounded awful and distorted, at first I thought it was the sound pressure levels, but it happened when playing soft too.

So I enlisted the help of one of the senior audio design engineers at Dolby Laboratoies, (that just happened to be my brother :)

We put the signal on a scope to see what was the issue. Every time the accordion was pushed or pulled without even playing a note it created a massive DC offset in the signal. This was because the mic diafragms were not vented.

Amps hate this. And speakers hate it even more.
It's a good way to actually blow some amps as well as speakers that do not have input protection.

DP