I found that distance-wise, the front L/R speakers need to be the same distance as the center from your litening/viewing position, otherwise, there are out of phase problems created as a result of the different distances of voice content speakers and this muddies the voice. I used a measuring tape and in my case, pushed the front L/R speakers back until they were the same distance as the center, which sits on top of my monitor.
Try it, it makes a huge improvement!
Try it, it makes a huge improvement!