When I play some .mkv files with 6ch DTS audio on my Nexus 7 using multiple video player apps, such as MX player and diceplayer, there is no sound and only picture. I try changing audio settings, but nothing happens.
Most of the popular Android players has removed DTS codecs support, so DTS would not work with them. It seems no way to fix the DTS issues. You could probably convert MKV with DTS sound to other video format, or load them in Plex on your PC/Mac computer and stream them to the tablet.