Back when I was young enough to have good hearing, I had to assist with some qualification testing in a lab. One part of the testing was done in an anechoic chamber. One of the things I remember most was the dead feeling inside the chamber. If you say something your voice seems to stop about a foot away.
A couple of years ago I received a pair of Bose QCII noise-canceling headphones. They have a little of that same dead feeling if you talk while wearing them. I do like them and use them for work meetings and watching videos on my PC.