well, how's this for out there? but i think i got it.
the short in the phones was worse than i thought, so i started tying to figure out some other cause - dirt, maybe?
the cords are an 1/8th inch. all the outs in the room are 1/4 inch. so, i need an adapter. i started playing with the connection to see if i could isolate it to one side of the cord, maybe.
what i began to realize is that i could get a fuller sound if i pulled the tip out just a bit. but, i couldn't get it back again after. and then it clicked.
what i'm thinking is that it isn't the cord, but the tip - that is, that this particular tip seems to have a microscopic defect on it that is not connecting properly in the adapter, but the other one doesn't. it's something most people probably wouldn't notice, but apparent on the high and low end; i think i'm getting a reduced signal due to the contact not snapping into place properly.
i happen to have a dozen of those adapters, somehow; i don't know how. but, i've experimented with a few and i'm getting closer to the proper "boom".
you can hear what i mean if you check out the first few seconds of the attached track. a drum-bass-guitar crash comes in after the arpeggio. through a good set of phones, it should get that "crush" effect on the bottom end. i was getting that through the shorted phones, but not getting it through the working ones; when i swapped the adapter out, i started getting it through the working ones.
it's a little different through each of the adapters, which just upholds the idea that there's some kind of mild contact problem.
you can hear it here, too, with the rising bass parts. that bass should saturate the mix - "BOOM". but, i wasn't getting the volume spikes - as though it was through a limiter.