The soundbar should be working in lieu the TV speakers, rather than working in addition to the TV speakers.
The TV speakers need the signal changed to analog, while the soundbar maintains a digital signal. This will separate the sound slightly enough to notice an echo, but it shouldn't be enough to notice a difference.
Using the soundbar speakers instead of, rather than with, the TV speakers would be my recommendation.
I recently bought new Samsung LED 3D TV and attached the Crystal Sound Bar to enhance the mediocre sound coming from the internal TV speakers. The problem now is that my comcast cable box and/ or the TV itself seem to be competing with the sound bar which is creating an annoying echo that I can't seem to get rid of. Help! Has anyone had this problem and if so can you tell me how to fix it? Thanks.