The connections
The quality of the source / sound influences the feel and power of the BassMe+. You can connect your BassMe+ as well as your headphones with the dual Bluetooth 5.1 output.
If the smartphone in question has the dual Bluetooth output = BassMe + Bluetooth headset / earpiece, AND/OR with a Bluetooth dongle (transmitter) connected to the smartphone. If the smartphone in question does not have dual Bluetooth output, connect the BassMe wired with your headphones.