if you can open it up and take out the drivers and test them by going left channel and right channel on the volume if you find the one that not playing sound remove it and push the cone of the speaker with something and look at the voice coil. if it’s black you might want to replace it with another one. and if its golden of copperish label it just in case you forget and plug it in the other side and test if works if and it does you might want go to best buy and go to geeksquad to ether get it replaced or fixed
you will have to get the charging pcb board and a hot glue gun to melt the black glue and to glue it place. first remove the front grill then unscrew the front drivers also remove the 4 screws on the side casing. next remove the 3 pin connector behind the speaker connections . then remove all 6 or 12 screws by the charging port BE CAREFUL their s a small ribbon cable that is easy to snap. then use the hot glue gun to melt the black glue or pry it off and feed it through and that is basically it your probably done.