Best spkr cable for biwiring bass drivers?

I'm running Krell 250m's into Meadowlark herons with NBS KS single wire.Would like to biwire the herons,but only looking to spend $300 used for a pr to run my bass drivers.What cable works best for bass?
thanks mike
At what frequency do the woofers crossover at ? Sean
What specific characteristics of your current sound are you unhappy with? Are you biwirng for the sake of biwiring, or do you have an objective?
Very Happy with the Bass Response from my Legacy's , using Acoustic Zen Satori.