I'm having this same problem with my D855 that I bought today.
It sounds like a loud hissing noise (like interference) and only seems to come out of the left ear piece, it's not noticeable when the music gets busy but during the quieter parts or where only one instrument is playing, it sounds horrible.
I've tried my Monster Turbine Pro Coppers and the bundled earphones, both produce the noise. It's also very apparent at different volume levels.
Updating from KitKat (4.4) to Lollipop (5..0) didn't help, as the problem is still there.
Looks like I'll be returning this phone already as I use my phone to listen to music a lot. It's a shame that such a fundamental problem should ruin what is otherwise a really nice phone. Ah well.