On my E92s, I am 99% sure telephone calls for Bluetooth came through all speakers as well.
I bet this loudspeaker is for certain tones or maybe chimes.
Maybe it sends white noise thru the cabin during phone calls to quiet them? Or some sort of noise cancellation use. Dunno.
But I am fairly sure calls go thru all/most speakers and not just this SINGLE one. It would be really obvious if that were the case. Keep brainstorming
