Happy New Year!
Ah, but that was 1999; we don't party like that any more.
Looks just like the ones used in the Echoplate. Could be from an EMT.
It sounds as though the loose wire on the voice coil is likely rubbing on the magnet structure; in other words it is a rubbing voice coil. The v.c. needs to be rewound. It should be an 8 ohm voice coil.
…the tech suggested we try to use another small amp to drive the speaker and rule out that there may be something going on there.
Wow really? seems like a far distance from the plate.Kind of you to offer running a file through yours. I'd be glad to take you up on that.
You can actually just drive the plate with music in the room too. Drums for instance can be in the same room as the plate.