I have a pretty new Dell Precision 5560, same one with Dell XPS 9510, I have an external speaker connected through its earphone jack port for audio, but found the speaker's volume is pretty low even with the maximum sound set on system setting's page, change to internal speaker, sounds normal, tried to connect this external speaker with other audio source, it sounds normal also, so, it must be something wrong with the Dell laptop here, can anyone give a clue what could be wrong or which settings I should look at?

Thanks,