I think Kelly is giving good advice here; this method works well for sealed speakers.
The notional benefit of hard high-passing would be to reduce distortion from relieved excursion on the main woofers. In this case, I don't think it would make much sense, or rather, e.g. the Vandersteen boxes, poor return for the expense, plus your amps really don't care that much. No idea what's in those boxes, can see a ton of cheap, stacked caps, but it just seems overall a bit baloney to me, and might be designed to specifically match one of their speakers.
The notional benefit of hard high-passing would be to reduce distortion from relieved excursion on the main woofers. In this case, I don't think it would make much sense, or rather, e.g. the Vandersteen boxes, poor return for the expense, plus your amps really don't care that much. No idea what's in those boxes, can see a ton of cheap, stacked caps, but it just seems overall a bit baloney to me, and might be designed to specifically match one of their speakers.