I have a European (n7000) note and I agree with most of you that the sound is just terrinble. I had many phones (P900, P1i, X1 etc.) and all were far better that the Note. I love this phone and I am deeply dissapointed but this issue. I tried the Neutron player suggested here and although there was a difference in the sound, it wasn't something that I would say "better", just different. In my Note the Neutron also produced some jitterring noise. As I said I tried many other players with no luck and I really can't see how a hardware issue can be fixed by software.
As many Note owners I am waiting for a solution to the USB digital audio output issue and hopefully I can add an external portable DAC/AMP.