Placing a moderate amount of weight on a component usually helps isolation feet to perform most efficiently (choice of material is critical, though; inappropriate materials can introduce unwanted resonance). As opposed to rigid coupling devices that often require heavy weights for mass-loading, components sitting on compliant feet usually work best with just a small amount of weight (grungebuster Dots make an excellent decoupling interface between a weight and component chassis). Moderate damping inside the chassis is usually beneficial also, (regular hardware-store rope caulk is ideal for this).