Issue using 5.1 surround sound speakers with headphones

I use 5.1 surround sound speakers normally when I play FFXIV. However, at night I turn off the speaker volume and listen through headphones (so that I won't wake up my kids).

The issue that I am having is that the voice acting from the cut scenes plays over the center channel. Thus when I am watching cut scenes and listening to the sound through my headsets, I can't hear the voice acting.

I am just wondering if there is some setting on FFXIV that will allow me to hear the voice acting through my headset but still let me keep the 5.1 speaker configuration.

Thanks.