Intermittent whistle/siren noise in cabin
 

Have a 2013 XC90 R-Design AWD with Premium Sound System. A bizarre whistle/siren noise (lasts approximately 1 second and volume varies) is intermittently coming from somewhere in the cabin (I think the speakers). However, it does not matter whether the stereo is on/off. Dealer has performed multiple software updates. Problem persists. Any thoughts?

Whistle / Siren sound from defost vents
 

Hello jtjr, did you ever figure out what the issue was with the cabin noise. I seem to have a similar issue on my 2013 Volvo XC90. When I'm going over 65mph and open my sun roof, I get this terrible whistle / siren sound coming from my front defrost vents. If I turn on my defrost it will almost go away.