The speakers in this setup alternate between KEF KS50s or Magnepan LRSs.
Those loudspeakers have no low frequency output. Run them full range and just drive the subs from the RCAs.
Balanced v high-pass
Balanced from an Ayre K-5xeMP preamp connects to Parasound JC 1 monoblocks and unbalanced to KEF KC62 subs that have an option for high-pass filtering. But that option requires replacing the balanced connections from the preamp to the JC 1s with unbalanced connections from the subs. Is the tradeoff worth it? Which is more important, balanced input or high-pass filtering? The speakers in this setup alternate between KEF KS50s or Magnepan LRSs.