I probably would use Mogami W3103. It is professionally engineered for the purpose but not priced for audiophiles. It should be fine within walls; I don’t think it’s rated for plenum use, if that matters to you.
P.S. The Belden 5000-series cable from Blue Jeans Cable also has very low R,L,C and is professionally engineered for speaker use. Blue Jeans says it’s UL-rated for in-wall use. It also would be a good choice.
P.S. The Belden 5000-series cable from Blue Jeans Cable also has very low R,L,C and is professionally engineered for speaker use. Blue Jeans says it’s UL-rated for in-wall use. It also would be a good choice.