Re: How far?
I live in a basic old terraced house in SE London, the type where the kitchen with a bedroom above sticks out the back, leaving a sort of dingy alcove.
With my LG G3 on my desk, by the rear window that looks out to the alcove next to the kitchen, I can still get music on my old 8 quid bluetooth headset on the front porch. About 15m and 2 or 3 brick walls.
I imagine a decent antenna and circuitry could at least double that to the middle of the road.