testing shielding on my acoustic probe?

[CopperCone]

So I put a tiny buffered smd microphone on a stick (shiskabob skewer) along with some ferrite and decoupling capacitors, shielded cable, twisted pair. It was kind of tricky to build but I basically used copper tape and some silver epoxy to make a seal going down to the braid/foil on the cable. The body of the microphone is metal and I connected it to the shield with the silver epoxy. It uses very thin wire (like 32 AWG for about 2 inches, the ceramic SMD cap and ferrite are basically super glued to the microphone, and dead bug solder bridged, then this is glued to a stick, 2 inches away the wires go to a larger tantalum cap/ceramic cap, then a large gauge 4 conductor double shielded cable is used, with 2 of the wires being used for power and 2 for signal (the power will be provided by a battery), the signal will go into a commercial filter box. The whole thing is coated with nonconductive epoxy up to the microphone body, then copper tape/silver epoxy is used to basically extend the shield over everything.. the only opening being the tiny slit for the microphone. The microphone is about the size of a 1210 package. I zip tied the 4 conductor cable to the stick, covered it well with epoxy and put heat shrink on top of it to make a half decent handle.

What's a good way to test immunity on it.. if I use an inductor I expect it to make some acoustic noise in addition to the fields it produces.

Since the microphone tops out at like 100KHz (really like 50KHz), I can't really use a proper antenna to make a field, because it would be gigantic..

Actually I don't even know if a low frequency antenna vibrates mechanically.

The only idea I had is to make some kind of foam block to stick the probe in that would hopefully dampen any mechanical vibrations, and maybe keep it in the same place to see if adding the foam reduces any of the signal levels. Something like a couch cushion came to mind, but I wanted to test it on fairly strong fields, meaning placing it right against the inductor face so its being exposed as much as possible, or making some kind of like air-gapped coil or helmholtz coil to make a field.

Would winding field-generating inductors on a piece of foam help, so there is foam between the wires and the core? Cotton sleeves on the magnet wire?

I was gonna use a nicely shielded directional industrial pickup coil good to around 70KHz to act as my indicator or field strength