I certainly don’t wish to muddy the waters but I have addressed the issue of materials for audio cones and feet elsewhere but it might be worth repeating. For audio cones, the way the rating of materials vs sound quality works is the HARDER the material the faster energy exits the system. Thus, NASA grade ceramic that’s almost as hard as diamond heads the list. Heat tempered and cryod high carbon steel next. Ordinary steel next. Then come aluminum, brass and carbon fiber which are way on down the Moh scale of hardness. The differences in the sound of these materials should be easy to hear on any reasonably good system. The shape of the cone is also important but not as much as the material. Iso stands are also subject to the differences in cone material, and cones should be placed under the component and under the stand, to avoid storing energy in the system.