Jake,
You are most welcome. It is fitting the 215 should go with RM-30’s I sold you a few years back. The sub was purchased at the same time as the RM-30s. Thanks to Shaukat (Shauk786) who gifted the surround cabinets to me. Glad they found a good home.
Thanks for mentioning the Nelson Pass active crossover. Beyond the Nelson Pass XVR1 there was the design Nelson gifted the DIY community, the 6-24 Bi-Amp active crossover. Super elegant solution, no feedback a few FETs to maintain signal. I like my Phil Marchand active XO, but this is next level, no feedback no op-amps. I had given up as the circuit cards have been sold out for the last couple years. Your mentioning got me to check DIY Audio store and low and behold they were in stock! I purchased the last two (needed for three channels). Been doing some modifications so no variable resistors and only polypropylene capacitors. All components ordered and on their way. Totally stoked! In the words of John Lennon, “Instant Karma going to get you”. It did, in the best of ways.
Good luck on the project and I am series about making my way to your neck of the woods one of these days as I would like to audition your ATC SCM-40’s. That midrange driver is legendary and I would like to spend some time with it.
Best