It seems to be a backup speaker for when the normal system can’t operate. I notice this if I’m driving and do a two-thumb MCU reset, and then disengage autopilot while the screen is black. I get midi-sounding autopilot sounds coming from the right footwell that are definitely not the normal source.
Was it hard to unplug? I took a look and it's way back there in the corner. I'm having the same issue. Sometimes I'll drive for an hour and won't hear it, and then the next time it won't shut off from one destination to the next. Very annoying, given the extremely high pitch.
UPDATE: I found a video about the cabin air filter location and found it referenced there. I think I'll unplug it for now also. It's driving me crazy...
Yes, this is the backup autopilot sound speaker. If the normal sound system in the ICE is offline for any reason, it can be driven directly from the APE (Autopilot ECU). So when rebooting the ICE with the scroll wheels you will hear it if AP needs to sound an alert. Note that unplugging the emergency speaker generates a fault that's reported to Tesla.