I buy another 16 capsules, because A) they are only $1.63 apiece, B) I ruined many of the first 10 learning to modify them cleanly, and C) I want to find two that are very closely matched in characteristics and performance. I buy a new pair of earbuds. I buy special frou-frou capacitors to improve the performance of the [very simple] circuit (see the Linkwitz page) that allows me to power the microphones without committing any grievous offenses against the inputs of the little Mackie 1202 mixing board I got on eBay a few weeks ago. All of these things (except the Mackie) have yet to arrive.
I learn a lot, really quickly.
The initial test device sounds a bit muffled in the midrange, though I do have to say that it makes a nice wide stereo image. (I will try to add a photo or two to this posting, and if I get it to the point where I’m recording any kind of really crisp sound out of it I’ll think about putting up an MP3, though at this point it’s just me on one instrument at a time, not very prepossessing.)