I have the XPS12 9Q33. I purchased an Accell B086B-008B-2 and Mediabridge ULTRA Series HDMI Cable from Amazon. Both audio and video are passed when I connect the hdmi cable to my tv or into my stereo receiver.
The StarTech MDP2HDS active adapter did not work.
Thanks for sharing that. I have added your post and parts of Thistle3595's post to the HDMI Audio FAQ.
Jim Coates -- 15 years on the Dell Laptop Audio boards -- since 2/6/04