I like Blue Jeans Cables and Audiosensibility. This BJC sub cable on Amazon is only 20 feet, but you can order direct from them. Audiosensibility are a bit more money but also very good quality.
https://www.amazon.com/Blue-Jeans-Ca...s%2C177&sr=8-4
http://www.bluejeanscable.com/
https://audiosensibility.com/blog/pr...interconnects/