I have a gogroove basspulse 5.1 ch speaker & I'm only getting vocal from the center speaker the front left & right & the rear

[cue-you-eye-n-see-why]

I have a gogroove bass pulse 5.1 ch speaker & I'm only getting vocal from the center speaker the front left & right & the rear left & right speakers play the background sound not the vocal. I'm using the speakers on my desktop with windows 7 32 bit ultimate on my msi z97 gaming 7 motherboard with the on board 5.1 sound card. Can any1 help me

 

[dudio]

Maybe I'm weird, but I think voice typically is targetted for the center speaker. If all other channels are playing what sounds appropriate other than central voice, then I think you're fine.
Disable any digital effects on the soundcard and system in case they are exaggerating things