I play my freelancer in window mode 99% of the time. It helps me do other things while trading/fighting (lol, I once read the forums while in the middle of a dogfight) and usually when I switch windows - the sound turns off.
But now all of a sudden - the people talking in the background (CARDAMINE CARDAMINE!) can be heard from my headphones every damn 2 seconds. It gets so annoying.
It happens that i somewhen hear the sounds of the game. For example when i'm trading and alt+tab out, somewhen i'll hear every tradelane segment i'm passing. It's nice to hear that, so if the lane ends or get disrupted, you can quickly rejoin the game and look if you had the luck to met a pirat, only NPC's or you actually reached the end of the lane.
In a brilliant tactical movement, i charged backwards.
I personally find the "noise pollution" helpful, since it plays TL and JG entering and exit sounds as well as shield impacts as well as CD ones.
The only way to get rid of it would probably to nuke your games audio folder as far a I know, get rid of all of the games audio, but I personally wouldn't recommend it.