When trying games, be sure to enable 7.1 in the game itself as well. Also SXFI with Stereo setting and with 5.1 or 7.1 might sound a bit different - I am talking about the settings in Creative's Windows app (I guess the one for macOS has about the same settings, only that I don't have a Mac around to try it). Finally, you should not forget about the Custom EQ setting - you might want to play with that one too alongisde enabling SXFI.

The billion-dollar question you asked has no good or bad answer, unfortunately. Sometimes, I KNOW for sure that the SXFI-enabled sound is not "as it's supposed to be" but I love it. Sometimes it's not that bad but I'd rather have pure Stereo sound. The truth is in the ear of the listener, after all...

It's refreshing to see a detailed review of this headset as there really doesn't seem to be much out there. I've been toying with the idea of making my own, but I'm giving myself time first.

I own these too, and I agree that the SXFI profiling can be a little confusing between using the various apps, and then knowing if the sound is 'right' - I'm yet to try an additional scan, I've been trying to figure out whether the sound is as intended, sometimes music will sound great, sometimes I'm just not sure, so I find I turn SXFI on and off depending on how uncertain I am. I've not tried movies yet, but did watch through a show on Netflix with SXFI on and it definitely added to the experience. The few games I've tried didn't go down so well with SXFI on, positional sound cues and the like were made worse, although I almost expected that at least with the one.

I get that it's intended for film, gaming, or even music, but I find anything with speaking (YouTube reviews, or even a call as I often wear them while working) just makes the person sound like they're stood in a big, cold, empty room with echo to boot. Maybe I need a fresh scan, or maybe I'm just right in turning SXFI off in such situations?

Any pointers to tell if the sound is 'right' based on your experience would be most welcome. I'd hope not to have to go scanning other people's heads to find the right sound for my own at least :)