listening is moving slower than i'd like (as always....story of my life....), but i just want to update that i am 100% certain at this point about what is happening with the distorted audio. there's no longer any ambiguity at all whatsoever.
for some reason, the cord in this specific pair of headphones is picking up a charge. it's very easily grounded - all i have to do is touch the tips. but, it's audible, too. because i'm just that type of audio nerd...
the issue, of course, is not persistent. it will sometimes stop, which is why i had so many false positives. i'm still going to need to do a lot of testing to figure out exactly what it is that is creating the field and whether certain pieces of equipment are acting as catalysts or not.
but, the basic reality that i'm living in some kind of magnet is now beyond question. what i'm going to do about it is a little less clear.
i'm opting strongly for building a tent to place around the recording space.