> I don't know if transparent Faraday cages are possible

Depending on your budget, you could faraday enclose the whole room / building rather than trying to do an individual device.

As related reading from back in the day: https://en.wikipedia.org/wiki/Tempest_(codename)

> While much of TEMPEST is about leaking electromagnetic emanations, it also encompasses sounds and mechanical vibrations.

Damnit. They're going to embed signals in the harmonics of the sound system, and invert the sound systems of neighboring connected devices to act as microphones. So you'll need a Faraday cage and a fully soundproofed and seismically-proofed room.

Of course then you can't use your phone inside your house/living room.

I'm already sold on the idea, you don't need to keep on selling it to me. :)

lol

They still sell landlines.