运动蓝牙耳机

Bluetooth signals can be reflected off solid objects so indoors, even if there is no line of sight, the signals reflecting back of the walls allows connection to be maintained. When you in an open space there is nothing for the signals to reflect off so you get connection issues.

Jaybird X2 / X3

Multi-paring support is no guarantee but it generally means that the bt driver firmware is more sophisticated and of better quality than the low-end drivers that some manufacturers license.