Sound Lab A-1 & the Ultimate differences

90493, I too use lead ballasts on my Soundlabs. I have three 25 pound bags of #7 lead shot wrapped in cloth and black gaffers (cloth) tape on each speaker. I also had a machine shop turn some steel cylinder stock into precisely the same leg diameter as the Soundlab. Adding about 2 and a fourth inches to the rear legs, allowed me to remove the aluminum Mod Squad tiptoes, and replace them with Simply Physics Delrin and Stainless steel feet. The Simply Physics feet can be adjusted to within a few thousands of an inch, while maintaining contact with the speaker frame. They do not "unscrew" away from the base, leaving an air gap. This added rigidity, and the ability to use a laser pin and bubble level, allowed me to precisely align the Ultimates for perfect imaging in my environment. As with all speakers and systems, its the little stuff that is so much trouble, that adds up and pays off.

HI Albert
I did the same only went the low-tech route and used steel washers to span the gap between the cone and the chassis. I like your approach better: better adjustability, but I was in a hurry. What can I say? Have you, by chance, ever had to re-tighten your panesls with a heat gun?

Yes, I called Brent at Soundlab and ask for the brand and model number of the heat gun that they use. Then I got the setting on the dial that they set the panels with, and marked that number with a Sanford Sharpie. Now if my speakers get cranky from the weather or excessive movement, I flash tighten them, using the same method the factory uses. The main problem with doing it after they are in the home is worrying about the grill cloth (spandex). It discolors and burns faster than the screen itself, if extreme care is not taken in the process.