I think it's the "no obstacles" issue here, since it does work when close and unobstructed. My Nexus 5x has no trouble playing over BT with other devices, such as in my car even when it's in a gym bag in the trunk, or in my home on a BT speaker a couple of rooms away. In both these situations, however, the BT device undoubtedly has a much better antenna than what can be packed into an earbud.