Tech Line Summary Article - Do you hear a booming or rumbling through the speakers when the cabin temperature is 55F or lower? Does it go away once the cabin heats up? We're aware of this issue and have it under investigation. If you get a vehicle in for this, remove the covers in the headliner for the ANC microphones and check if the insulating foam is damaged or folded over as shown below. We've found this may be the reason for the noise.