I am trying to play .mkv format videos that have dts audio using my z5500 speakers to decode the dts. Im running vista ultimate x64 and no matter what i do i cannot get the dts to work. im running it out of my onboard soundcard via optical cable spdif, i have all my codecs and settings to pass through dts streams since the z5500 has a built in dts decoder. nothing, sometimes i get some audio but its so choppy u cant understand it. If i use ac3filter i get Dolby Digital to my z5500's but im trying to get DTS since its suppose to be better. Any help would be really great!!!