Kmplayer surround sound not working

so, i decided to use a pair of speakers that i had lying around, and turn my 2.0 speakers into 3.1. i got it working in windows sound test thingy-dingy but when i tried to configure kmplayer to use them all, it only uses the front 3 and not the bass speaker. i think it might be using the centre as a bass speaker aswell, but im not sure. it works perfectly in most games that ive tried it with, but not all.


any help appreciated,