Weird volume control issue

Hello everyone

I recently purchased an Auzentech X-Plosion Cinema 7.1 pci audio card. My hopes were to finally achieve surround sound for gaming on my computer which is hooked up to my reciever and to a 5.1 speaker system.

Everything works great, my games finally output 5.1 audio, and i can hear zombies behind my in L4D now =D

When testing things out, i did notice that audio behind me was also audible slightly through the front speakers as well. At first, i thought, eh, must be the way computer games decode the audio, its not meant for recievers and dolby digital/dts etc.

Just recently, I did notice this. My volume control does not seem to control my volume! If i put it to 0, I still get audio. Now what makes it interesting, when its 0, the front left and front right speakers are still 100%, but the center, rear left and rear right are off. I tested this out in the driver configuration.

So I search around, found this topic, but didn't seem to find a proper fix, but i'm not really worried about turning off the audio, i can simply turn my reciever down for that, what i'm worried about, and bear with my wording, because this is kinda weird to explain.

Basically, I think when I hear faint audio from behind me coming through my front speakers, its as if two audio sources are coming through, and I can only control the overall surround sound, but there is something else keeping some weird stereo audio going, which is probably why I hear faint sounds in the front, when the audio source is clearly behind me in some games

in contrast, if i play Call of duty on PS3, the surround sound is crystal clear, I hear everything around me perfectly and can pin point the source really easily, but on the pc games, its alot more difficult,

now has anyone encountered this strange problem, i can live with it, but gone through a few sound solutions so far and can't seem to fully fix this surround sound audio problem i'm having

btw I am using Win7 64 bit