Spark MINI accepts 3 different input ways (Aux In / Bluetooth Audio / USB Audio) to stream music, but please note that you can only use 1 input at a time. If the 2 or 3 of them are connected to Spark MINI at the same time, only one of the inputs will work properly.
Aux In will be prior to all the inputs. The 2nd priority is Bluetooth Audio, and the 3rd is USB Audio. If your music input is not working properly, please make sure there is no higher priority input occupying.