I loved the cone of silence, in the one of the movie remakes of Get Smart, they used a high tech version.Just throwing this into the mix for possible causes... 5G. <ducking>
And for private conversations, well, we have the "Cone of Silence"...
Cone of Silence (Get Smart) - Wikipedia
en.wikipedia.org
I made/ improvised a version for a very high noise environment, well, kind of loud.
I worked on a transmitter that made a loud droning sound. So I took a large box with eggshell foam in it and put it over my head when on the phone (cell phones weren't available at the time).
It kind of worked.
Thanks
Joel
