My husband would have problems making a call out to me when he was in his Model S. This would be making a call through the car with his paired iPhone. It would always be the first call he made after getting into the car. Believe he could hear me but I couldn't hear him. All he had to do as a workaround was, as soon as he made the call, adjust the volume on the left scroll wheel (he said even one notch seemed to do the trick) and the sound volume problem wasn't there when he did. I don't seem to have this as a problem on my Model 3 but you might want to try the scroll wheel and see if it helps. It's possible I do have the problem, but because when I call out I always automatically without thinking adjust the volume level as the call is being made, it doesn't show up for me. It was always very frustrating for us when he would call me and we couldn't seem to talk to each other without me hanging up and him redialing. As I said he said it only affected the first call that he made during that car trip.