@lewm , the sub chassis, a 1" thick aluminum plate is hanging from 4 dampened springs that are attached to the underside of the plinth (Sota calls it the cover) top surface. The Three adjustable feet are threaded to posts that travel through holes in the sub chassis and also attach to the underside of the plinth upper surface. Nothing touches the sub chassis but the four springs, the main bearing and the tonearm board. The duct cover is hinged to the back surface of the plinth (cover). As supplied by Sota there were two rubber pads on the front upper surface of the plinth that the dust cover rested on. I did not like this arrangement as it left an open slot of about 1/16th inch all the way around the turntable. Fortunately, the dust cover hinges are adjustable. I removed the rubber pads and applied 1/4" wide, 1/16" thick heavy felt strips all the way around turntable and adjusted the hinges so that the dust cover sits flat on the felt completely closing off the upper chamber of the turntable. The sub chassis is further isolated from sound by the skirt that I made which closes off the bottom chamber of the table. There just happen to be two pictures of the table on my system page. The picture without the maple skirt shows the table as supplied by Sota with the two rubber pads at the front corners. The picture with the temporary maple skirt show the table with the felt gasket on the sides. The felt is brown so you have to look closely to see it. I had yet to install tthe felt along the front and back.
When I get a chance I'll take a picture of the table as it is now. I'll also run another sine sweep with the microphone under the dust cover to see how much quieter it is. I just have to figure out how to get the mic's cable in there without breaking the seal. I'm hoping to get another 5 dB of attenuation, maybe more? Whatever, the turntable sounds great.