Interesting that Dell is again making a monitor speaker-bar and is apparently now again building monitors with the necessary built-in mounting .  Specs say that it only connects with USB (for power and audio-signal). That usually means it has a "sound card" built in. So, no way to add more power or sound output.  The speaker-drivers inside look pretty small anyway. I think these are mainly to add basic sound capabilities in a business environment. 
I found the Soundbar very quiet. Is there any patch or option to make it louder? Or do I have to add additional speakers?
XPS 8940, Dell Slim Soundbar SB521A