Everything About Digital Audio FAQ
Q: What is Surround Sound ?

A: Surround sound, employing multichannel audio, encompasses a range of techniques for expanding and deepening the sound of an audio source. This is achieved by the implementation of additional audio channels and speakers. Human hearing's three-dimensionality can be virtually achieved with sound sources above and below the listener. To that end, a multichannel system encircles the audience (left-surround, right-surround, back-surround), as opposed to essentially two-dimensional "screen channels" (center, front left, front right).
Refer to Wikipedia surround sound article for additional information.

Q: What is Dolby Digital ?

A: Dolby Digital is the marketing name for a series of lossy audio compression technologies developed by Dolby Laboratories. It includes several similar technologies, which include Dolby Digital, Dolby Digital EX, Dolby Digital Live, Dolby Digital Surround EX, Dolby Digital Plus, and Dolby TrueHD.
Refer to Wikipedia Dolby Digital article for additional information.

Q: What is Music Server ?

A: A Music Server is a dedicated device for playing and managing a music library.
Refer to Stereophile article for additional information.