You can simulate a reverb by playing a sound in a room and placing microphones around the room to pick up the natural reverb. A room set up for this purpose would be a chamber reverb unit.
A chamber reverb unit is a space set up so that the natural reverb of sound produced in it can be recorded.
The chamber reverb concept is simple but can have many variations with different rooms, room treatments, microphones, microphone placement, and a sound origin placement. While the chamber reverb unit is simple in concept, applying it in practice is not. One problem is transport. You can set up everything in a studio once, but it is difficult to move this setup to a different place.