Virtual-Hideout posted a review on the Vantec USB External 5.1 Audio Adapter

The Vantec 5.1 audio adapter isn't for everyone. If you already have a soundcard in your system capable of outputting 5.1 channels, you probably won't need this, which adds another external device to the mix. However, if you have a laptop or other portable system, most of which only have stereo outputs, this adapter will be helpful, especially if you watch movies a lot and would like to take full advantage of your 5.1 speaker system. Watching movies with a full 5.1 channels is far better than listening to them in down-converted stereo mode. This is the audio adapter's intended use, as it quickly and easily adds 5.1 output support to any system, and does it well.

Vantec USB External 5.1 Audio Adapter Review