For maxed-out staging, my final install had moved the monitors still farther away from the front wall, if with somewhat less proximity than I practice down the hallway as shown next.

With Martin's analog crossover of zero digital latency, the potential for proper time alignment bakes in. It asks very nicely for equivalent free-space sub placement. Regular households probably can't get away with it. They'll settle for a shallower soundstage. Nothing wrong there. It's just a hobby. Back to folding our bass dipole style. In this execution the triple-slot box is curvaceous, its stacked Ply build extra rigid, its quad wire-suspension footers virtual floatation off the floor, its banana quad an excuse to power each woofer with its own amp.

True, I play offensively broken record on the matter. Just so, active RiPol bass' individual adjustments and reduced room interactions meant that true 25Hz performance with compact monitors visually and sonically appropriate for a smaller room came into sharp focus—far sharper than passive speakers could possibly net under identical conditions. This system hams it up a bit. The one shown above applies the same general concept with more budget ingredients. My main system scales up beyond even this one. If there is just one thing I learnt in two dozen years on this job—hopefully there's more for another day—it's this: actively filtered stereo 2.1, ideally with a folded-dipole sub, is the best real-world solution for superior bass in untreated rooms.

The white arrow points at the XO², a 2x200W TI-based class D amp with power supplies, attenuators and frequency selectors all in dual mono.

Just then a misplaced remote for my usual Lifesaver Audio Gradient Box II crossover had its output stuck at -38dB to be unusable. Using Martin's XO² as a stop-gap meant Stereo 2.1 Lite so merely filtering the sub whilst running the mains open. This limited the quasi cardioid benefits to just the 1st octave. To do Stereo 2.1 Proper and run my new sub to ~120Hz required cutting the monitors mirror-imaged. For that my mysteriously absentee remote had to beam down again; or this dbx 234xs ring my bell. How could a chunky metal wand just disapparate? Blame the cat?

These Aiyima-sourced 48V/5A power bricks for the sound|kaos XO² back its TI-based 200W/4Ω mono amps with 240W/ea.