The lower enclosures were dampened with carpet padding and automotive headliner fabric. Just some minor dampening to breakup any resonance that might happen, and help to clean up things for a little more clarity. A friend helped me with the final sanding prep using 400 grit. I learned a lot about final prep work, and these cabinets are really looking great. I did a quick stacking of the components to check proportions and get some idea as to what they will look like complete.