If anything, data over audio would be easier in an anechoic chamber since you don't have to worry about reverb or background noise.
US Military guidelines do require acoustic isolation of all SCIFs (Secure Compartmentalized Information Facilities). You just need isolation, though; deadening the rooms is not really necessary.
US Military guidelines do require acoustic isolation of all SCIFs (Secure Compartmentalized Information Facilities). You just need isolation, though; deadening the rooms is not really necessary.