Depending on your system. Audyssey should flatten out any nulls you get in the mid frequencies. If you find that dialog is getting drowned out and your system supports it, look to add a bump around the 200hz as that will help amplify most dialog without bumping up the special effects that are outside of that spot.

Anthem: AVM60, Fosi DAC-Q5
Axiom: ADA1500, LFR1100 Actiive, QS8, EP500, M3, M3comp, M5