In a more serious vein, if DK was seeking a superior non resonant material for the speaker chassis, how did choice fall on Aluminum? Aluminum billet rings like a bell when struck. Magnesium for one is a lighter and less resonant metal. More exotic, non metallic materials are used by other manufacturers. One material no one has applied to speakers yet is Pumice, a natural vulcanic glass foam. Extremely light, rigid, and sonically extremely inert. Cannot be used for outer surfaces because of its texture, nevertheless could be used in non exposed load-bearing areas.