since I got my Lumia 800 I am hearing sounds coming from Modem itself - that classic "doo doo doo di di doo" () - it happens on both speaker and on headphones out. It doesn't happen always! And it is most likely interference inside the phone, because with A2DP headphones it doesn't happen either.
Is it just problem of my specific phone or is it known global issue with all 800s?
// I got my phone with some older drivers, updated to 12070 with Zune. I then quickly updated to 12072 because of the nasty volume bug.