For additional data, I have an Emotiva XPR-1 amp that powers two subwoofers. I have been using the Beldon 10awg stranded speaker wire (available from Blue Jean Cable). I just recently converted to using some very old Audioquest Midnight 10awg cable. The increase in bass strength, power and quality was absolutely outstanding!
http://www.audioquest.com/archives/speaker_cables/spiraled_hyperlitz/images/midnight_c.jpg
The Audioquest Midnight is all solid-core conductor design that 17awg, 19awg and 21awg conductors (3 x 17awg for bass).