I recently changed my external sound card from a Presonus 1818VSL audio interface to a smaller version the 44VSL, when im in gameplay Helis and planes sound like if they were right in my face and they can actually be 100 meters away, when i shoot my gun sounds like if it was behind a wall but the impact of my bullets or any other gun shot sounds bloody loud, there is no stereo separation everything is in mono and with bad eq, makes it impossible to play on KOTH servers for instance, audio is really important in this game.

How can i fix it? i tried everything that i could think of but nothing has worked yet.