It ain't over until the cone of silence descends on the fat lady

I've been following the developments in acoustic cloaking for some time now. The utility of hiding a noisy presence on the concert stage or orchestra pit, in a recording studio or a stealth vehicle, or just for sound-proofing your garret, lair, or garage seems obvious to me. Here's a popular account of one of the most recent developments, a purely acoustic cloaking structure. Here's the research paper proper. You've got to love a physics paper discussing isotropic acoustic metamaterials and sonic crystals.