Run length


Room layout dictates the sub is on the opposite wall. Not ready to run a wire across the floor. It would be 26 feet.

To skip the floor run I would have to go up and down inside the wall. That would add another 18 feet for a total of 44 feet.  Too long?  Will be using plain old 14AWG cord.
ibmjunkman
No problem. Ears just aren't that sensitive to such low bass as you're talking with a sub. For example, just that ordinary wire alone would be crap and you'd hear it as crap even at just 5ft. But with subs you can get away with cheap wire just fine. 
OP do yourself a favor, 10/2 or 12/4 Soow or Sjoow is great cable and a LOT tougher. 10AWG zip cord the smallest I’d be using even with just a meter run.. Bass loves heavy copper. In wall or under the structure, Soow or Sjoow cable.. Good ol USA materials on Ebay. .25-1.00 usd a foot.

I don’t mess around with cable size, when it’s easy to run GOOD cable at no extra cost. The same way sound moves is the same way I treat cable.

The lower the frequency the heavier the cable but the higher the strand count of copper. The higher the frequency (MIDS) the larger the strand size and a lower the count of silver clad/tungsten, to a single stinger for highs and UHF. Pure silver.

I keep spools, it’s Dirt cheap, 99.99 copper, 300/600vac, and you can bury it.. 50 year life EASY... Armor it up as it comes out of the wall (optional)..

Regards
Have you considered a wireless connection, like the below from SVS? They seem to be getting pretty common.  I have a similar situation, and have been wondering about it.


https://www.svsound.com/blogs/subwoofer-setup-and-tuning/how-to-set-up-a-wireless-subwoofer