Because of the way that DTS-X Information is encoded, any Blu-ray player that supports DTS-HD Master Audio and bitstream output will support DTS:X. DTS actually wraps up the DTS:X information into a DTS-HD Master Audio wrapper that works with existing players and receivers. When a DTS-HD Master Audio soundtrack is sent over HDMI to a DTS-X receiver or processor in bitstream mode, the receiver or processor detects that it is actually a DTS-X track and processes the sound accordingly.
To ensure you get bitstream audio at max quality, please set “BD-Video Secondary Audio” to “Off” in the settings menu.