Dolby digital Plus Give Upto 7.1 Discrete Channels of High-Fidelity Surround Sound
If your system includes only Dolby Digital, you'll still get 5.1 channel surround sound, with the Highest-Quality Dolby Digital.
Dolby Digital Plus is an audio technology based on Dolby Digital 5.1, the established standard for cinema, broadcast, and home theater surround sound.
In Short Dolby Digital Plus Is 2nd Generation Of Dolby Digital.