I didn't have this problem until I joined a server using the FH2 Toolbox once.
Then I could hear all kinds of noises, tanks, shots, all as if they were right next to me. Not only did this happen in FH2, but also regular BF2.
I went straight for switching off EAX and saved my profile. I didn't bother to switch EAX back on and went ingame. All seems to be back to normal...
Yeah, worked for me too. Though, when I tried to turn EAX (with Hardware sound on High) back on, the problem immediately returned.
FYI, I don't have a sound card, but onboard sound.