Define "vastly expanded"? You can't beat the Smyth A16. But it's $4,000... Try turning crystalizer on, setting a flat EQ, and set surround to 100. If crystalizer does not do it for you try a slight boost between 2k and 8k in EQ. But always keep surround at max. I have never tried the A40's as headphones but I imagine even "cheap" good cans would be an improvement in staging and imaging. E.g. PC37X, HE-4XX, HD598. The AD700X is usually well regarded in the FPS positional audio department, maybe also try that again with the G6 vs. the mixamp.