@asvjerry It's a linear tracker, which I tried to build without compromising rigidity or adjustability. That means expensive off-the-shelf stuff from Igus (costs more to make equivalent quality, IMO), three indexed linear slides and two slides with brakes on the sleds. Lots of machining too. I prefer Panzerholz to natural wood because it's rigid and has great damping properties. Lots of decisions peculiar to the layout - like where to hang wires and air hoses, etc.
Just installed this weekend, so still finding things that don't quite work together - luckily, little things. But the concept is proved - it's the most adjustable arm I've ever heard of, like tangentiality to the nearest 5 microns - the length of a medium large bacterium. Clarity improved from bass to treble, soundstage wall to wall and rock solid, speakers disappearing. That's over the former unit, also an air linear tracker.