dsper - I'll chime in regarding spikes and outriggers. I don't claim any esoteric knowledge, but developing the spikes was in my cabinet design wheelhouse. This story might seem happenstance, but that's how a lot of high performance audio actually unfolded. There wasn't a playbook, nor was their internet or a particularly 'sharing' culture regarding innovations. We went to shows, mostly CES in those days, but we were too busy with managing our own display to pay much attention to what anyone else was doing.
So, from my perspective, we invented / developed spikes, granting that others may have done so independently. By that I mean that we didn't copy spikes from anyone else. Here's how it came about. The models 01 and 02 were 'bookshelf' speakers, which could be used upright or on their sides; no feet were appropriate. The 03 was floor-standing and its base was a plinth, smaller than the footprint. Our listening room and measurement lab had hardwood floors. A rocking speaker could be shimmed with a matchbook or penny or dime. The 04 had no base - we used 4 rubber feet. The problem became obvious when we moved to Nandino Blvd (final factory site) in 1980. Jim's first lab had carpet, and subsequent rooms had padded floors and carpet to help suppress the first floor reflection. In that configuration, the speaker would recoil.
The aha moment of what was happening came when comparing time-domain scans around 1981 while developing the CS3. Things looked as expected when scanning each driver separately (in the actual cabinet), but became slurred when all three drivers were driven simultaneously. Some experimentation and math revealed that recoil, especially from the woofer, was moving the tower enough to spoil the time alignment, especially of the short wavelengths of the tweeter. Spiking to the floor was the obvious solution. Since our tilt-back design put more mass at the back of the cabinet, we added two spikes at the back and one in front with no adjustment necessary because 3 points define a plane. Those spikes were in the plinths, which were significantly inboard of the footprint of the speaker, but it worked and worked well.
Flash forward to 1988 while developing the CS5 with its marble baffle which raised its center of mass considerably. I enlarged the plinth to the entire footprint, but the three pin arrangement could still fail if the speaker were bumped by the hypothetical rambunctious child. So, the pins moved to the 4 corners, where they had to become adjustable for less than flat floors. Those pins employ a zero-clearance thread with very tight tolerances. They allow virtuallly zero slop; and they can be turned over to put a rounded end on finished floors instead of the points to penetrate carpet.
Over time all the bases moved outboard, the lighter speakers retained 3-point support and the heavier ones 4-point, all as far out as possible. The addition of outriggers came later, after my time. They would geometrically increase the stability, and as long as they could not flex, then I see no down-side. I don't know the forces that drove the outriggers, whether market or tech, but I suspect market since the perimeter pins are quite effective in themselves.
Question: do any of you hear sonic improvement using the outriggers?
