Allright, this might a little strange problem, and it's not very severe either, but it still puzzles me.
Now, I play TrackMania Nations quite a lot, and the game works perfectly fine on my comp. Then a while ago, I decided to re-watch all the Red vs. blue show, but there was too much highfrequent sound (the bass on my speakers sucks). So in an attempt to make the sound better, I opened up this old eq program (was installed on our comp by default) called soundeffect (or MSI Sound Manager) I turned on the equalizer, and increased the quality of the sound. Now I decided to open up TMN, but I get really dissapointed when the sounds doesn't work properly. It turns out the engine sound comes out from the screen's speekers, but almost is too faint for me to hear. The rest of the sounds (crashes and music) comes out from the speakers. Now I try to increase the volume of the screenspeakers, but they aren't affected. I try to mute the speakers, but they aren't affected. I try to use my headset, the sound still ejects from the screen.
. I tried turning the eq of, tried changing amount of speakers, changing midi, weave, front, synthesizer, but nothing just seems to affect it. 
Does anyone have any idea as to how to fix this problem? because I sure don't.
EDIT: Oh, if I decrease the overall sound to zero, they mute, but then I can't hear anyting in my headphones either.