I had the same problem! My phone makes the hiss sound which almost makes it sound like my ear is ringing when I hold the phone up to my ear. It only does it when the screen is lit up. I had a post earlier this week that described this same issue. I'm glad I found someone else that has had the problem because I had the same issue with only 2 or 3 people hearing it out of 8 to 10. I just talked to AT&T today and they are sending me a new one tomorrow. I hope I have better luck with it.