I believe, when we explore like this, one of our main senses is listening. I was listening hard so as not to open a door on a private conversation or a seminar. There was a notice of a seminar so I did not want to walk in on them.
The sound of me blundering into the room seemed to have disturbed no one at all so I could retreat at my leisure taking just a few moment to observe my first ever, totally silent conference presentation in, what I calculated to be, a conference for the hearing impaired.
Breakfast was equally fascinating. I had never considered it before but I think breakfast in a hotel is a hubbub of conversation coloured with the clatter of cutlery on crockery. So - remove the hubbub and the breakfast room becomes an amazing sonic experience.
The hearing impaired conference was having an early start. They filled the breakfast room before I arrived. Not only did they make no sounds but the mass of bodies actually absorbed any other sounds in the room so this breakfast room resembled an anechoic chamber. No sound created, and all existing sounds sucked out of the space. I stepped into this sonic vacuum.
The most impactful observation was however as the crowd began to leave. I saw a group of 2 or 3 moving out of the room ahead of a colleague. One of the men had left a trinket on the table. His colleague left behind, gathered it up. He had no way to attract his friend's attention so had to dash across the breakfast room and tug at a sleeve, handing across the item.
One of those things I had never considered, how to attract attention across a room when everyone is hearing impaired. Perhaps they were all speech impaired too since there were no sounds at all.
Then came the final fascination of the morning. The group left the room and sound seemed to enter in their wake. Normal sound levels came back and all non conferees seemed to be able to converse again above a whisper.