When I use the 812 alone at full range, and from half its sound capacity, there starts to be an internal resonance as if something is touching the plastic of the speaker box inside, and starts to vibrate. I've tried it with all four 812s I have at home and they all do the same. I would like to know if anyone has tried this test, connecting directly from a mobile phone or computer to the rca inputs and check if it makes this vibration that I said. Do the test and for sure the same will happen to you, it seems that the plastic composite box can't handle the low frequencies in full range mode. I look forward to feedback from anyone who wants to help understand this abnormal resonance. Thanks
I too have this issue. I own two F1 units. The newer unit #2, vibrates at low frequency Bass guitar signals when at full volume. Unit #1 however sounds tight and pure when maxed at outdoor gigs. Rattle was loud enough with unit #2 I had to set the "with sub" switch to on position (which stops the rattle) to get through the gig. I called Bose, then sent the warranted unit #2 to Jeffersonville IN. July 9th for repair. The latest message is they repaired it and it will arrive wed. July 14th. We have another outdoor gig July 17th, I will report back.