Wemfan,
W/out going into to much detail, in order to make the speakers more mobile, the crossovers where cramed to fit into bottom of the speakers. Because of this resulted in compromises in parts quality, inductor crosstalk, and rather small iron core coils that saturated too quickly, resulting in decreases in dynamics & bass quality.
The NC crossovers simply replicated B&W's specs, but w/ high grade parts, a more spacious layout, and a huge copper air coil. It also bypasses the overload circuit, which also compromised sound quality.
As I said before, I could live happily w/ the speakers as stock. The NC crossovers, and other mentioned tweaks make a great speaker that much better. As an aside, I powered these with a 150W amp for years before upgrading. The great thing w/ 1st class speakers is that as you upgrade whats in front of the chain, everything just sounds better.
Dave 72- I believe the S3 crossover simplified the topology, used better crossover coils, eliminated the Zobel network across the woofer, & eliminated the APOC protection. Also, I think the S3 tweeter was ferro-fluid filled, whereas the S2 tweeter was not. Am unsure whater the firbercrete mid-tweet unit remained removable or not.
Cheers!
