I would say the range, unobstructed, is roughly 10-13 meters.
It starts to get more picky when you throw walls and floors in between the casting source and the speaker.
Also note that the signal is interrupted and spotty if you have your casting source, say a phone, on your lap and are using a wireless Xbox one controller in between the source and the speaker. I always had to set my phone to the side while I played games.