Sorry, I've never encountered a Neutric connection. Any line out RCA from any amp is the same as one of the two RCA line outs from your preamp. That means it is a full spectrum line level signal.
Based on your opening statement I assumed you had the sub working fine. Where in the world does this Neutric connection that needs the HF speaker out information go to? The speaker out would mean an amplified signal meant to drive a tweeter. At least that's how I'm reading your post.
Based on your opening statement I assumed you had the sub working fine. Where in the world does this Neutric connection that needs the HF speaker out information go to? The speaker out would mean an amplified signal meant to drive a tweeter. At least that's how I'm reading your post.