Question- can the XMC-1 mic be used with REW? I understand that REW only uses 2 brands of USB mics with spec values.
It's been a while since I used REW, but historically - you could use any mic you wanted and load its calibration curve. Some use mics with a "batch" calibration curve, others prefer to have an individually calibrated mic. For me, I feel like if I am going to the trouble of doing a room calibration - I should spend the small amount extra to get an individually calibrated mic. So, I went with the Cross-Spectrum Labs UMIK-1 even for my XMC-1. But, you could use your XMC-1 mic and its calibration curve w/REW if you wanted - but the XMC-1 has a batch calibration curve.
XMC-1 DIRAC Full; Oppo 105/Roku Ultra to Panny AE4000 w/106" screen; UltraRendu to LH Labs Geek Pulse X-Infinity; nCore nc400's or Prima Luna Premium Prologue to Maggie 1.7's; Rythmik F25; XPA-5 to CC-470v3 Center/ERD-1's; Thorens TD166 MkII/Denon DL207/XPS-1; 5-zone Sonos w/Def Tech AW5500's @ deck/pool/master bath & Sony SS-MB105/Polk R10 @ great room & kitchen. Two headphone setups: Hifiberry/BasX A100 and Allo BOSS/Schiit Asgard 2 (each to Senn 600's). PC w/Airmotiv 3b's. Roon user.