So I upgraded my older Def Tech 80's to the Pro Series 1000 and have been constantly having to reposition the ProSub 1000 after watching those action pack thrillers. Good thing I had some slack in the power cord after watching Thor into the Darkness. So anyway I thought and thought as to how I could stop this beyond attaching a leash to the wall. So I remembered at work we had some 1" wide industrial strength Velcro adhesive strips. So I flipped the Sub upside down and took a small bladed screwdriver and removed the glued in rubber foot on the bottoms of the feet. Then I cut the Velcro about 2" long so once in place it could be trimmed with a razor knife to the contoured shape of the foot. After cleaning the floor where the sub sets so the adhesive would stick good I measured it off, removed the adhesive protective strips and easily set in place with a little downward force. Ha! it doesn't move any now yet can be easily take up if needed.
