Earlier quoted context omitted.
Wouldn’t SOOW (or THHN/THWN-2 )in 14 or 16 gauge be appropriate for this?
My speaker's manual says the following: > Please always use a good quality loudspeaker connection cable from an audio dealer. To prevent impairment of sound quality, we recommend cables with cross-sections of at least 2.5 mm² for lengths up to 3 m and at least 4 mm² for lengths above 3 m. Interestingly, the table present in the printed manual is not present in the one on the internet. IIRC, recommendation for 100W up…
The shielding might not be needed, the low cost for single conductor wire is why I mentioned it.
The person I was responding to was mentioning they can’t find appropriate “main power” cable. (So probably not in the USA )