5.1 Computer Speakers with digital in?

Does anyone know of any computer speakers that have a digital input (optical/coax), not just og in. Or does anyone know of a device that converts digital in to og 5.1 out? My computer has only one stereo 3.5mm out, but its not 5.1. I do have a 5.1 optical out, but all the 5.1 PC speakers I have seen only have 3 separate 3.5mm inputs for Front, rear, center and sub.