I have a set of Plantronics sports bluetooth headphones, and I can routinely walk 30 or 40 feet away from my iMac or phone and still hear them OK. I can even go to the bathroom which is outside my office are and in another room across a hall and still enjoy music/podcasts.

Physical walls are of course, the major factor in signal loss, rather than pure distance. It seems 2 walls between my headphones and the host are OK, but 3 walls is pushing the friendship a little.