Insul-Fab of Texas sells 80db metalized film with plastic lamination on one side for strength. You wallpaper with it or put it behind your drywall to metal studs with each edge overlapping on the conductive side. Use RF attenuating vents on the air ducts and use glass laminated with silver plated, stainless steel, carbon black, from Don-Tech. A metal door with rfi gasketing around the jam seal and you have an 80db shielded room as long as you use an isolation transformer.
Then if you add the cone of silence your room is complete.
Blackdog I am just pulling you leg thanks for the information
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