So I have started using Scotchbrite pads as sound insulation/deadener in my speakers and have found it to work quite well, as expected. The next question is how to keep it in place, glue or staples? A third idea also keeps popping into my vacuum chamber, and that is using tension, or more accurately, compression. By getting the Scotchbrite in a large sheet and cutting it properly, it should fit and hold itself in place just by using an interference fit. Basically you cut it one or two inches larger than the inside circumference of the box and squeeze it in, it should hold in by itself. Another idea just hit me,; Velcro !
Problem is I have not found any large sheets of Scotchbrite bigger than 8" x 11".