Just bought a Creative Sound Blaster X3 amazing piece of kit btw. The SXFI tech on it though is broken when you go and run the 7.1 audio test the left front, left side, and left rear all come out of the left front speaker location. Center comes out of the center. Right side mirrors the left with the problem to.
It's their software/drivers, as always. I just got the X3 a few weeks back and love the hardware and SXFi, but hate the software. For some reason, if you're using the Creative drivers and/or software (even the mobile app, it seems), the SXFi gets stuck in stereo mode as soon as you make pretty much any adjustments, regardless of what you do or how you set it up. Having speakers configured as 7.1 in Windows makes no difference. If you turn off SXFi and just use SBX, it works perfectly fine, but SXFi is stuck in stereo mode, making it virtually useless.
My personal solution - I don't use the Creative driver and software (because thankfully, with the X3, they're basically not needed). I just created my SXFi profile, uploaded it to the X3, made all the adjustments I wanted...and then switched to the generic USB Audio 2.0 Windows drivers. They can be set to 7.1 mode with no issues, and the SXFi is amazing with headphones in full 7.1 mode once you get accustomed to its sound. Everything works perfectly fine like this, you basically just can't switch SFXi profiles and/or adjust the internal EQ (you're stuck with the profiles you uploaded to the device the last time you ran it with Creative drivers).
There's even a bonus - if you use the X3 with something like Voicemeeter that basically keeps the device active at all times, your PC will likely not go to sleep with the Creative drivers, because once again, they use the stupid "Legacy Kernel Caller" stuff that can't be whitelisted in Windows (possibly due to a MS bug). If you use the generic USB Audio 2.0 driver, you can whitelist it no problem and your PC will have no trouble going to sleep even with the X3 being kept "active".
It's a bit of a joke that the flagship feature of the X3 doesn't work properly, but that's how it seems to be right now. Hope they fix it. I thought about returning the unit before I found the workaround, but the SXFi is so awesome (IMO) that I'm willing to keep it as long as I can work around their bugs.