Background noise

There is a little background noise instead of silence in my game. I’m using monogame 3.2 and SharpDX 2.5.0. Device is Lumia 620. There is no any noise in other software.
What could be the reason?

On my Lumia 520 is same problem. When i adjust devices volume on 0, noise is stopped, but when back volume up, noise continue. Maybe problem is in MediaElement or code in monogame but I don t know … When i make in native, it is no problem, or when i add MediaElement into new Windows phone project c# without monogame… i would like know where is problem or how do it without noise, too. Please, can you help us? Thank you : ).

Same here on 520 but I though it’s phones hw as I can hear it more or less in other sw, no noise in emu though.