Interesting .... and how do they do that then? What kind of shielding provides 100% negation of RF frequencies? I don't think that the plastic that the units are made from would protect against RF interference, which might suggest that it is not RF shielding that improves the SQ. I only know of one material that would stop absolutely any frequency from penetrating, and it would certainly be impractical. I mean all RF, that's a pretty broad spectrum.