Dolby Digital - DirecTV

I have a LG 4K 55" TV with a LG 2.1 sound bar attached to the TV via a high speed HDMI cord. When I inquire using the TV what type of digital sound format the TV is receiving from U-Verse it tells me "Dolby Digital". Will Dolby Digital 5.1 and 7.1 sound systems if installed on my system operate to their potential and create that premium sound under "Dolby Digital" or will the sound be less then desirable.

This question, "Dolby Digital," is about DirecTV channels, programming, equipment, and sports.