[Gary NE]

My wife and I plan to purchase a 2012 S60 T5 from my elderly aunt who no longer drives. It has 45K miles and seems to generally be in fine condition. The car's at our home now and we took it for a couple of test drives today. Everything seems great except for a noise that invariably begins between 60 and 70 mph, and increases in frequency with speed (as well as decreasing in frequency as speed is decreased). It sounds like medium-pitched radio static. Some might call it a buzz. We're certain it's coming from inside the car, this is not wind noise. The radio is off (not just turned down). We haven't been able to pinpoint the source, but it does sound electronically generated, and sounds a lot like it's coming from one or more speakers. I was driving, with my wife in the front passenger seat, and to both of us the sound seemed to be coming from somewhere ahead of the driver.

Some 15-20 years ago, we had a Chevy Suburban that made what we recall as a nearly identical noise, which I think also varied with speed in the same way, and I think that turned out to be coming from the OnStar speaker(s). I don't recall what the solution to that problem was.

This sound isn't very loud, but definitely too loud for us to just live with.

This is the only Volvo we've had any experience with. Can anyone offer advice on possible cause and solution? The nearest Volvo dealer is 2 hours away, so a DIY fix would be nice if possible.