In reply to:

What is the difference between DTS and Dolby Digital?



http://www.audioholics.com/techtips/specsformats/dolbydigitaldts.php

In reply to:

Does my DVD player need to be compatible for DTS



Yes it does. If it is, the DTS logo will be on it somewhere.

In reply to:

Do I need a single speaker for the back for DTS?



No. DTS is 5.1 just like Dolby Digital.