I don't find that the response you were given was accurate. You don't need special speakers, you just need a digital decoder.
All I did was buy a TOSlink to 1/8" optical cable to plug in my laptop into my Dolby Digital 5.1 receiver. It worked perfectly, at least once I went into the Control Panel and enabled Digital Output in the Realtek Sound Manager (located on the SPDIF panel).
Oh, I also had to make sure it was set to 48 KHz, and from then on I was in full Dolby Digital.