You 'can' run regular speaker wire in wall but if you ever move or the house is inspected for some reason and they notice it as not FT4/CL3 rated(cdn specs) or at least CL2 then you nay have a problem.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70