I just got my SP2309W and yes, you definitively need the audiobar with the power adapter.
It's too bad, really, I really don't get why dell didn't have it built into the monitor like for other models.
This also means that when you are done with the audio it will not power down itself.. you will have to power it
down manually... Rather annoying...
Well, the SP2309W is the best alternative to the extremely expensive Apple cinema displays with camera
speakers and microphone. I guess it's of "ok" quality.